OT: Converting miles/km

[Christian Weisgerber]

I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.

So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).

WHAT?

Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.

If nothing else, it's faster to type on a calculator.

I think that's hysterical.

[Aidan Kehoe]

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.
If nothing else, it's faster to type on a calculator.
I think that's hysterical.

The old units were completely neglected when I went to school, which is
unfortunate, it’s routine that we need to convert between vulgar feet and
inches for height to centimetres in daily life, or between vulgar stones and
pounds to kilograms. What I learned from my father (born 1945, went to school
before it was neglected) was that a kilometre is 5/8 of a mile, which helps in
converting the speed limit signs in Northern Ireland to what my speedometer
shows.

I will attempt to bear ln(5) in mind going forward!

[Garrett Wollman]

Post by Aidan Kehoe

Post by Christian Weisgerber
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.

pounds to kilograms. What I learned from my father (born 1945, went to school
before it was neglected) was that a kilometre is 5/8 of a mile, which helps in
converting the speed limit signs in Northern Ireland to what my speedometer
shows.

That's the approximation that's much easier for mental arithmetic, and
similarly, 8/5 when converting the other way. Otherwise, 1.609344 is
the exact conversion, and 1.609000 is good enough for almost every use
(unless you're doing weird stuff like survey miles, which are based on
the old foot of 1200/3937 meter,[1] rather than the "international"
foot of 0.3048 m).

However, an approximation that has actually proved useful to me is
that 1 m/s ≅ sqrt(5) mi/h. As everyone knows, sqrt(5) ≅ 2.236068, or
2.2 if you only need two significant figures, which is much easier
to remember than 3600/1609.344 ≅ 2.236936.

-GAWollman

[1] One will note that this conversion defines a meter to be exactly
39.37 inches, although that's never how it's actually phrased.
Sometimes that's a more convenient conversion than the modern one even
if it's no longer exact.

[Steve Hayes]

Post by Aidan Kehoe
The old units were completely neglected when I went to school, which is
unfortunate, it’s routine that we need to convert between vulgar feet and
inches for height to centimetres in daily life, or between vulgar stones and
pounds to kilograms. What I learned from my father (born 1945, went to school
before it was neglected) was that a kilometre is 5/8 of a mile, which helps in
converting the speed limit signs in Northern Ireland to what my speedometer
shows.

My rule-of-thumb is that a kilometre is 0.6 of a mile. The instrument
in the car showed tenths, rather than eighths of a mile.

Post by Aidan Kehoe
I will attempt to bear ln(5) in mind going forward!

It doesn't work in reverse?

[Hibou]

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.

Afflict? Sometimes I wonder how many more times I'm going to hear
Germans criticising how we do things.

Post by Christian Weisgerber
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.
If nothing else, it's faster to type on a calculator.
I think that's hysterical.

I'm afraid I don't see the problem. Just assign 1.609344 to a memory
cell. That's what I do. A shortened version is fine for mental
arithmetic - better than ln(5) - and if one has forgotten 1.6... but has
a calculator, what's wrong with tapping 2.54 x 12 x 5,280 / 100,000?

Simples!

[Hibou]

Post by Hibou

I'm sorry, I don't know where to post this.  I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.

Afflict? Sometimes I wonder how many more times I'm going to hear
Germans criticising how we do things. [...]

Thinking about that, it occurs to me that I have allowed myself to
criticise how other nations do things - the Americans, the French, and -
yes - even the Germans.

I withdraw my remark.

[Peter Moylan]

Post by Hibou
I'm afraid I don't see the problem. Just assign 1.609344 to a memory
cell. That's what I do. A shortened version is fine for mental
arithmetic - better than ln(5) - and if one has forgotten 1.6... but
has a calculator, what's wrong with tapping 2.54 x 12 x 5,280 /
100,000?

That's all very well if you can remember that there are 5280 yards in a
mile. I'm afraid that my school days are far behind me, and Ancient
History was one of my weakest subjects.

I'm still just hanging on to the fact that an inch is about 25 mm, but
that's probably the magic number that's next to fade from my memory.

I still remember that a mile is about 8/5 km, but it's unlikely that
I'll ever again visit a country that uses miles, so that too will soon
fall into the bin for useless facts.

[Hibou]

Post by Peter Moylan

Post by Hibou
I'm afraid I don't see the problem. Just assign 1.609344 to a memory
 cell. That's what I do. A shortened version is fine for mental
arithmetic - better than ln(5) - and if one has forgotten 1.6... but
has a calculator, what's wrong with tapping 2.54 x 12 x 5,280 /
100,000?

That's all very well if you can remember that there are 5280 yards in a
mile.

<Cough>

Post by Peter Moylan
I'm afraid that my school days are far behind me, and Ancient
History was one of my weakest subjects.
I'm still just hanging on to the fact that an inch is about 25 mm, but
that's probably the magic number that's next to fade from my memory.
I still remember that a mile is about 8/5 km, but it's unlikely that
I'll ever again visit a country that uses miles, so that too will soon
fall into the bin for useless facts.

SI is all very well for science, and BTUs and the like give me the
heebies, I admit; but Imperial units - ounces, pounds, inches, feet,
miles, are often well adapted to everyday life, and live on in a largish
chunk of the world. The whole world (as far as I know) uses knots and
nautical miles in the air, and on and under the sea. So, quite recent
history, then.

Where Britain has gone wrong is in metricating half-heartedly. We drive
for miles, and then fill up in litres - yet milk mostly comes in pints
and quarts. Tables of clothing sizes are sometimes in inches and
sometimes in centimetres (and probably inaccurate anyway). And so on.

We should be champions in mental arithmetic - though the evidence is
that we're not.

[occam]

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.
If nothing else, it's faster to type on a calculator.
I think that's hysterical.

You do use Google search? Try typing '1 mile = ? kilometers' in the
google search bar. Answer = 1.60934.

P.S. The google search bar has come a long way. It can be the source of
a lot simple-ish maths solutions, thanks to rudimentary AI.

[Bertel Lund Hansen]

Post by occam
You do use Google search? Try typing '1 mile = ? kilometers' in the
google search bar. Answer = 1.60934.

You don't even need the "? kilometers".

[Hibou]

Post by Bertel Lund Hansen

Post by occam
You do use Google search? Try typing '1 mile = ? kilometers' in the
google search bar. Answer = 1.60934.

You don't even need the "? kilometers".

The calculator in Ubuntu knows all sorts of conversion factors.

If one selects 'Miles', the default conversion is to Parsecs.

Better make sure the battery's charged.

[occam]

Post by Bertel Lund Hansen

Post by occam
You do use Google search? Try typing '1 mile = ? kilometers' in the
google search bar. Answer = 1.60934.

You don't even need the "? kilometers".

Yes you do, unless you want to choose one of: 1760 yards/1.60934 kms/320
rods/1.70108e-13 light-years etc. There is more to a mile than kilometers.

[Bertel Lund Hansen]

Post by occam

Post by Bertel Lund Hansen

Post by occam
You do use Google search? Try typing '1 mile = ? kilometers' in the
google search bar. Answer = 1.60934.

You don't even need the "? kilometers".

Yes you do, unless you want to choose one of: 1760 yards/1.60934 kms/320
rods/1.70108e-13 light-years etc. There is more to a mile than kilometers.

Of course. It was understood that you wanted kilometers - as you wrote.

[Peter Moylan]

Post by occam

Post by Bertel Lund Hansen

Post by occam
You do use Google search? Try typing '1 mile = ? kilometers' in
the google search bar. Answer = 1.60934.

You don't even need the "? kilometers".

Yes you do, unless you want to choose one of: 1760 yards/1.60934
kms/320 rods/1.70108e-13 light-years etc. There is more to a mile
than kilometers.

Yes, but Google doesn't give you those unless you ask for them. It
assumes that you want kilometres.

But maybe it's country-dependent, because it didn't even give me the
American spelling. Perhaps in the UK the default is set to rods, poles,
or perches.

[occam]

Post by Peter Moylan

Post by occam

Post by Bertel Lund Hansen

You do use Google search?  Try typing '1 mile = ? kilometers' in
the google search bar.  Answer = 1.60934.

You don't even need the "? kilometers".

Yes you do, unless you want to choose one of: 1760 yards/1.60934
kms/320 rods/1.70108e-13 light-years  etc.  There is more to a mile
than kilometers.

Yes, but Google doesn't give you those unless you ask for them. It
assumes that you want kilometres.
But maybe it's country-dependent, because it didn't even give me the
American spelling. Perhaps in the UK the default is set to rods, poles,
or perches.

No, alas, the default choice of Google _is_ kilometers. But it can be
made to change its mind if enough of us ask for the miles to light-years
conversion.

[Christian Weisgerber]

Post by occam
You do use Google search? Try typing '1 mile = ? kilometers' in the
google search bar. Answer = 1.60934.

My point wasn't really to give practical advice on unit conversion--
I assume we can all manage--but to laugh at the sheer absurdity of
two entirely unrelated numbers working out to approximately the
same, purely by chance.


PS: I use Google for currency conversion.

[Mike Spencer]

Post by Christian Weisgerber

Post by occam
You do use Google search? Try typing '1 mile = ? kilometers' in the
google search bar. Answer = 1.60934.

My point wasn't really to give practical advice on unit conversion--
I assume we can all manage--but to laugh at the sheer absurdity of
two entirely unrelated numbers working out to approximately the
same, purely by chance.

It's also very close to the magic number (1 + sqrt(5))/2, the solution to
1/x = x - 1

Post by Christian Weisgerber
PS: I use Google for currency conversion.

[Helmut Richter]

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.

... the English-speaking world with the exception of Ireland, Canada,
Australia, New Zealand, and South Africa and some others.

I think the term “United Kingdom and USA” would have been shorter and
slightly more accurate.

Post by Christian Weisgerber
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.
If nothing else, it's faster to type on a calculator.

And easier to remember than 1.609344. But when will you need such precision?
For instance, when you drive on German roads outside villages, you must
reduce your speed to 31.0685 mph whereas the rough rule 1 mi = 1.6 km would
have allowed you 31.2500 mph.

I like much more those thumb rules that actually allow you to estimate orders
of magnitude, e.g.:

1 year ≅ π · 10⁷ sec ≅ 31415926.54 sec

or

1 year ≅ √10 · 10⁷ sec ≅ 31622776.60 sec

or, only for those wanting more precision, the arithmetic mean of the two
which has three leading digits correct.

--
Helmut Richter

[Bertel Lund Hansen]

Post by Helmut Richter
And easier to remember than 1.609344. But when will you need such precision?
For instance, when you drive on German roads outside villages, you must
reduce your speed to 31.0685 mph whereas the rough rule 1 mi = 1.6 km would
have allowed you 31.2500 mph.

I haven't neede it, but just for fun I have calculated the Danish speed
limits in miles. If you want round firgures, it's:

50 km = 30 mi
80 km = 50 mi
110 km = 70 mi (2 km too much)
130 km = 80 mi

[Phil]

Post by Bertel Lund Hansen

Post by Helmut Richter
And easier to remember than 1.609344. But when will you need such precision?
For instance, when you drive on German roads outside villages, you must
reduce your speed to 31.0685 mph whereas the rough rule 1 mi = 1.6 km would
have allowed you 31.2500 mph.

I haven't neede it, but just for fun I have calculated the Danish speed
50 km = 30 mi
80 km = 50 mi
110 km = 70 mi (2 km too much)
130 km = 80 mi

I'm not sure how common this is, but the speedometer in my car has
scales for both mph and km/h, so in principle I don't need to convert.
In practice, though, I have the above table in my head, from the old
days. It's easily remembered because the right-hand column corresponds
to the usual preferred values for UK speed limits.

[Silvano]

Post by Phil

Post by Bertel Lund Hansen

Post by Helmut Richter
And easier to remember than 1.609344. But when will you need such precision?
For instance, when you drive on German roads outside villages, you must
reduce your speed to 31.0685 mph whereas the rough rule 1 mi = 1.6 km would
have allowed you 31.2500 mph.

I haven't neede it, but just for fun I have calculated the Danish speed
50 km = 30 mi
80 km = 50 mi
110 km = 70 mi (2 km too much)
130 km = 80 mi

I'm not sure how common this is, but the speedometer in my car has
scales for both mph and km/h, so in principle I don't need to convert.
In practice, though, I have the above table in my head, from the old
days. It's easily remembered because the right-hand column corresponds
to the usual preferred values for UK speed limits.

And the left column corresponds to the usual preferred values for speed
limits in Continental Europe, AFAIK.
You should add 30 km (reduced speed in some parts of cities) and 120 km
(seen from time to time).

[Bertel Lund Hansen]

Post by Silvano
And the left column corresponds to the usual preferred values for speed
limits in Continental Europe, AFAIK.
You should add 30 km (reduced speed in some parts of cities) and 120 km
(seen from time to time).

That would be 30 mi (two much) and 75 mi.

[on purpose]

[Stefan Ram]

Post by Phil
I'm not sure how common this is, but the speedometer in my car has
scales for both mph and km/h, so in principle I don't need to convert.

These days, even regular folks can afford small computers at home,
and with a BASIC interpreter, anyone can whip up his own conversion
program. The programming language BASIC is so simple that anyone
can pick it up. It can handle math terms straight out of the box.

MILES.BAS

10 PRINT "MILES TO KILOMETERS CONVERTER"
20 PRINT "-----------------------------"
30 INPUT "ENTER MILES: "; M
40 K = M * 1.60934
50 PRINT M; "MILES ="; K; "KILOMETERS"
60 END

TRANSCRIPT

MILES TO KILOMETERS CONVERTER
-----------------------------
ENTER MILES: ? 2

2 MILES = 3.21868 KILOMETERS

[Sam Plusnet]

Post by Phil

Post by Bertel Lund Hansen

Post by Helmut Richter
And easier to remember than 1.609344. But when will you need such precision?
For instance, when you drive on German roads outside villages, you must
reduce your speed to 31.0685 mph whereas the rough rule 1 mi = 1.6 km would
have allowed you 31.2500 mph.

I haven't neede it, but just for fun I have calculated the Danish speed
         50 km = 30 mi
         80 km = 50 mi
       110 km = 70 mi (2 km too much)
       130 km = 80 mi

I'm not sure how common this is, but the speedometer in my car has
scales for both mph and km/h, so in principle I don't need to convert.
In practice, though, I have the above table in my head, from the old
days. It's easily remembered because the right-hand column corresponds
to the usual preferred values for UK speed limits.

Also, most modern cars can be persuaded to display speed (digitally) in
either mph or kph to suit your current needs.

[Bertel Lund Hansen]

Post by Sam Plusnet

Post by Phil
I'm not sure how common this is, but the speedometer in my car has
scales for both mph and km/h, so in principle I don't need to convert.
In practice, though, I have the above table in my head, from the old
days. It's easily remembered because the right-hand column corresponds
to the usual preferred values for UK speed limits.

Also, most modern cars can be persuaded to display speed (digitally) in
either mph or kph to suit your current needs.

Now that you mention it. I had completely forgotten, but I can change
the setup of mine to show miles. I dare not activate it, though. With my
failing memory I would get speeding tickets.

[Aidan Kehoe]

[...] Also, most modern cars can be persuaded to display speed (digitally)
in either mph or kph to suit your current needs.

My then wife was using our car for her own reasons at one point in 2019 or so,
and living on the border I rented a Citroën in Northern Ireland since that was
the closest business that would do that for me. It was a UK model, and its
digital speedometer was in miles per hour with nothing in the manual to suggest
how to change that. So for four or five days I was doing the mental arithmetic
in the opposite direction from my norm. Not a big deal in the grand scheme of
things, but an annoyance.

[Athel Cornish-Bowden]

Post by Aidan Kehoe

[...] Also, most modern cars can be persuaded to display speed (digitally)
in either mph or kph to suit your current needs.

My then wife was using our car for her own reasons at one point in 2019 or so,
and living on the border I rented a Citroën in Northern Ireland since that was
the closest business that would do that for me. It was a UK model, and its
digital speedometer was in miles per hour with nothing in the manual to suggest
how to change that. So for four or five days I was doing the mental arithmetic
in the opposite direction from my norm. Not a big deal in the grand scheme of
things, but an annoyance.

We had the opposite problem, a long time ago, in 1975 or so. We had to
get from Cork to Killarney for a meeting. We didn't rent a car
ourselves, but went with a colleague who had himself rented a car.
There was nothing to indicate whether the car expressed the distance in
miles or km, or the speed in miles/h or km/h. Likewise with the signs
along the road. Today it woukd be easy to ask Google Maps the distance
from Cork to Killarney (89 km in fact: it me a whole 10 s to detrmine
that) but there was no Google then, and we didn't know whether Ireland
had switched to km. As the roads were mostly like English country lanes
it wasn't easy to judge distances.

[Aidan Kehoe]

We had the opposite problem, a long time ago, in 1975 or so. We had to get from
Cork to Killarney for a meeting. We didn't rent a car ourselves, but went with
a colleague who had himself rented a car. There was nothing to indicate whether
the car expressed the distance in miles or km, or the speed in miles/h or
km/h. Likewise with the signs along the road. Today it woukd be easy to ask
Google Maps the distance from Cork to Killarney (89 km in fact: it me a whole
10 s to detrmine that) but there was no Google then, and we didn't know whether
Ireland had switched to km. As the roads were mostly like English country lanes
it wasn't easy to judge distances.

The speed limits are now in km/h (change was in the 90s, if I remember
correctly) and marked as such. Once you see a speed limit without the units
marked you are in the North and it’s mph.

And the roads are now better, though Cork to Killarney is not as undemanding a
drive as much of the east coast.

No crash, then? (I’m sure you would have mentioned it if you’d written off the
car.)

[Hibou]

Post by Sam Plusnet
Also, most modern cars can be persuaded to display speed (digitally) in
either mph or kph to suit your current needs.

Our recent hire cars have displayed the speed limit, as read from limit
signs via their cameras. It is often wrong, displaying a recent speed
limit, not the current one - unsurprisingly, since in France there are a
variety of signs that set the speed (a crossed-out place name, for
instance), the camera lens may be dirty, a lorry may mask a sign, and so on.

Apparently, the crazy EU has made this flawed system the basis for
mandatory speed limiters (and the crazy UK has followed suit). If you
run into someone stuck at 30 kph on a 130 kph autoroute, that's probably
the reason.

"However, our experience of such systems suggests they can get it wrong.
In one instance, a car's traffic sign recognition system picked up a
30mph sign on a turning off a dual carriage and dramatically slowed
down, despite the fact the car was actually travelling along the outside
lane" -
<https://www.parkers.co.uk/car-advice/speed-limiters-what-they-mean-for-you/>

God preserve us from government!

[Athel Cornish-Bowden]

Post by Hibou

Post by Sam Plusnet
Also, most modern cars can be persuaded to display speed (digitally) in
either mph or kph to suit your current needs.

Our recent hire cars have displayed the speed limit, as read from limit
signs via their cameras. It is often wrong, displaying a recent speed
limit, not the current one - unsurprisingly, since in France there are
a variety of signs that set the speed (a crossed-out place name, for
instance), the camera lens may be dirty, a lorry may mask a sign, and so on.
Apparently, the crazy EU has made this flawed system the basis for
mandatory speed limiters (and the crazy UK has followed suit). If you
run into someone stuck at 30 kph on a 130 kph autoroute, that's
probably the reason.

When we were first in France 37 years ago the authorities weren't as
fussy about enforcing speed limits as they are now. Once driving to Aix
I reached 159 km/h (not 160 as I intended, but my courage failed me) on
the motorway. I wouldn't even think of that today, but I was younger
then (and my wife wasn't in the car).

Post by Hibou
"However, our experience of such systems suggests they can get it
wrong. In one instance, a car's traffic sign recognition system picked
up a 30mph sign on a turning off a dual carriage and dramatically
slowed down, despite the fact the car was actually travelling along the
outside lane" -
<https://www.parkers.co.uk/car-advice/speed-limiters-what-they-mean-for-you/>
God preserve us from government!

[Bertel Lund Hansen]

Post by Hibou
"However, our experience of such systems suggests they can get it wrong.
In one instance, a car's traffic sign recognition system picked up a
30mph sign on a turning off a dual carriage and dramatically slowed
down, despite the fact the car was actually travelling along the outside
lane"

My father has some friends who steadily run into that problem on the
road that they use every day.

When you say that the system is mandatory in EU, does that mean that we
are not allowed to disable it? I select speed according to my gps, and
that is 5 kph faster than the speedometer reading. It's pretty much been
the same with every car that I rented before I bought one.

[Hibou]

Post by Bertel Lund Hansen

Post by Hibou
"However, our experience of such systems suggests they can get it wrong.
In one instance, a car's traffic sign recognition system picked up a
30mph sign on a turning off a dual carriage and dramatically slowed
down, despite the fact the car was actually travelling along the outside
lane"

My father has some friends who steadily run into that problem on the
road that they use every day.
When you say that the system is mandatory in EU, does that mean that we
are not allowed to disable it? I select speed according to my gps, and
that is 5 kph faster than the speedometer reading. It's pretty much been
the same with every car that I rented before I bought one.

Yes, car speedos are allowed to over-read but not under-read. GPS is
more accurate (except in tunnels).

It seems you can disable the speed limiter, but you have to do that
every time you start the car (and the maker may perhaps bury the option
several menus down).

[Bertel Lund Hansen]

Post by Hibou
Yes, car speedos are allowed to over-read but not under-read. GPS is
more accurate (except in tunnels).
It seems you can disable the speed limiter, but you have to do that
every time you start the car (and the maker may perhaps bury the option
several menus down).

A technical question that you may not be able to answer:

I always use cruise control. Will one in a a new car automatically
activate the sign reading limiter? If so, I'm screwed.

[Silvano]

Post by Hibou

Post by Sam Plusnet
Also, most modern cars can be persuaded to display speed (digitally)
in either mph or kph to suit your current needs.

Our recent hire cars have displayed the speed limit, as read from limit
signs via their cameras. It is often wrong, displaying a recent speed
limit, not the current one - unsurprisingly, since in France there are a
variety of signs that set the speed (a crossed-out place name, for
instance), the camera lens may be dirty, a lorry may mask a sign, and so on.
Apparently, the crazy EU has made this flawed system the basis for
mandatory speed limiters (and the crazy UK has followed suit). If you
run into someone stuck at 30 kph on a 130 kph autoroute, that's probably
the reason.
"However, our experience of such systems suggests they can get it wrong.
In one instance, a car's traffic sign recognition system picked up a
30mph sign on a turning off a dual carriage and dramatically slowed
down, despite the fact the car was actually travelling along the outside
lane" -
<https://www.parkers.co.uk/car-advice/speed-limiters-what-they-mean-for-you/>
God preserve us from government!

Japan was already wiser 40 years ago, but the more appropriate name is
probably "speed limit warnings".
A friend gave me a ride there when an alarm sound went off.
- What does this noise mean?
- I was driving at over 100 km/h (the speed limit on their highways at
that time). We have a warning system on all our cars.
- What about all those cars overtaking us? Do they produce the same noise?
- Yes.

[occam]

Post by Silvano

Post by Hibou

Post by Sam Plusnet
Also, most modern cars can be persuaded to display speed (digitally)
in either mph or kph to suit your current needs.

Our recent hire cars have displayed the speed limit, as read from limit
signs via their cameras. It is often wrong, displaying a recent speed
limit, not the current one - unsurprisingly, since in France there are a
variety of signs that set the speed (a crossed-out place name, for
instance), the camera lens may be dirty, a lorry may mask a sign, and so on.
Apparently, the crazy EU has made this flawed system the basis for
mandatory speed limiters (and the crazy UK has followed suit). If you
run into someone stuck at 30 kph on a 130 kph autoroute, that's probably
the reason.
"However, our experience of such systems suggests they can get it wrong.
In one instance, a car's traffic sign recognition system picked up a
30mph sign on a turning off a dual carriage and dramatically slowed
down, despite the fact the car was actually travelling along the outside
lane" -
<https://www.parkers.co.uk/car-advice/speed-limiters-what-they-mean-for-you/>
God preserve us from government!

Japan was already wiser 40 years ago, but the more appropriate name is
probably "speed limit warnings".
A friend gave me a ride there when an alarm sound went off.
- What does this noise mean?
- I was driving at over 100 km/h (the speed limit on their highways at
that time). We have a warning system on all our cars.
- What about all those cars overtaking us? Do they produce the same noise?
- Yes.

This sound warning is optional on my car (i.e. can be disabled). The
visual warning (on the GPS display) however, is not. As soon as you go
over the speed limit, the colour of the limit indicator changes (to
red). The absence of a sound warning is a blessing, rather than a
handicap. It is annoying most of the time, and can be dangerous at other
times e.g. when you are accelerating for a good reason.

[Aidan Kehoe]

Post by occam

Post by Silvano

Post by Hibou

Post by Sam Plusnet
Also, most modern cars can be persuaded to display speed (digitally)
in either mph or kph to suit your current needs.

Our recent hire cars have displayed the speed limit, as read from limit
signs via their cameras. It is often wrong, displaying a recent speed
limit, not the current one - unsurprisingly, since in France there are a
variety of signs that set the speed (a crossed-out place name, for
instance), the camera lens may be dirty, a lorry may mask a sign, and so on.
Apparently, the crazy EU has made this flawed system the basis for
mandatory speed limiters (and the crazy UK has followed suit). If you
run into someone stuck at 30 kph on a 130 kph autoroute, that's probably
the reason.

A mandatory warning is part of the law, but actual restriction is not, so
should you be in those occasional situations where breaking the speed limit is
safer than following it, you can (usually, depending on your manufacturer) just
keep the foot on the accelerator despite the alarm.

Post by occam

Post by Silvano

Post by Hibou
"However, our experience of such systems suggests they can get it wrong.
In one instance, a car's traffic sign recognition system picked up a
30mph sign on a turning off a dual carriage and dramatically slowed
down, despite the fact the car was actually travelling along the outside
lane" -
<https://www.parkers.co.uk/car-advice/speed-limiters-what-they-mean-for-you/>
God preserve us from government!

Apart from things like seatbelt laws, high taxes on tobacco, enforced rules on
food safety, regulation of medication? Or are you completely fine with easily
avoidable death and major disability, shorter and worse-quality lives, mass
poisonings, more mass poisonings? The middle option saves on taxes given if you
die at 63 from lung cancer you won’t draw much in the way of state pension, so
there is a financial but not humanitarian argument for it. There’s no argument
for the rest.

Post by occam

Post by Silvano
Japan was already wiser 40 years ago, but the more appropriate name is
probably "speed limit warnings".
A friend gave me a ride there when an alarm sound went off.
- What does this noise mean?
- I was driving at over 100 km/h (the speed limit on their highways at
that time). We have a warning system on all our cars.
- What about all those cars overtaking us? Do they produce the same noise?
- Yes.

This sound warning is optional on my car (i.e. can be disabled). The
visual warning (on the GPS display) however, is not. As soon as you go
over the speed limit, the colour of the limit indicator changes (to
red). The absence of a sound warning is a blessing, rather than a
handicap. It is annoying most of the time, and can be dangerous at other
times e.g. when you are accelerating for a good reason.

[Silvano]

Post by occam

Post by Silvano
Japan was already wiser 40 years ago, but the more appropriate name is
probably "speed limit warnings".
A friend gave me a ride there when an alarm sound went off.
- What does this noise mean?
- I was driving at over 100 km/h (the speed limit on their highways at
that time). We have a warning system on all our cars.
- What about all those cars overtaking us? Do they produce the same noise?
- Yes.

This sound warning is optional on my car (i.e. can be disabled). The
visual warning (on the GPS display) however, is not.

From what I saw at that time, Japan was ridiculously underdeveloped on
some items (washing machines, squat toilets - well, they moved on in
these 40 years and we should learn a lot from them about modern toilets,
see <https://en.wikipedia.org/wiki/Toilets_in_Japan>), but it was much
better than Continental Europe on other items (bullet trains, fax etc.).
But even they did not have GPS displays 40 years ago.


As soon as you go

Post by occam
over the speed limit, the colour of the limit indicator changes (to
red). The absence of a sound warning is a blessing, rather than a
handicap.

I agree, but you can't have a visual warning on the GPS display before
the invention of GPS displays. No idea about the present situation over
there.

[Rich Ulrich]

On Sat, 21 Sep 2024 21:11:31 +0200, Silvano

Post by Silvano

Post by occam

Post by Silvano
Japan was already wiser 40 years ago, but the more appropriate name is
probably "speed limit warnings".
A friend gave me a ride there when an alarm sound went off.
- What does this noise mean?
- I was driving at over 100 km/h (the speed limit on their highways at
that time). We have a warning system on all our cars.
- What about all those cars overtaking us? Do they produce the same noise?
- Yes.

This sound warning is optional on my car (i.e. can be disabled). The
visual warning (on the GPS display) however, is not.

From what I saw at that time, Japan was ridiculously underdeveloped on
some items (washing machines, squat toilets - well, they moved on in
these 40 years and we should learn a lot from them about modern toilets,
see <https://en.wikipedia.org/wiki/Toilets_in_Japan>), but it was much
better than Continental Europe on other items (bullet trains, fax etc.).
But even they did not have GPS displays 40 years ago.

I found that article on toilets in Japan to be interesting. I once
read a whole book about bathrooms, so it could be that I am easily
amused.

I learned that I can take one away ('toilets') from the set of things
never yet connected to the internet.

Post by Silvano
As soon as you go

Post by occam
over the speed limit, the colour of the limit indicator changes (to
red). The absence of a sound warning is a blessing, rather than a
handicap.

I agree, but you can't have a visual warning on the GPS display before
the invention of GPS displays. No idea about the present situation over
there.

[Janet]

Post by Rich Ulrich
On Sat, 21 Sep 2024 21:11:31 +0200, Silvano

Post by Silvano

Post by occam

Post by Silvano
Japan was already wiser 40 years ago, but the more appropriate name is
probably "speed limit warnings".
A friend gave me a ride there when an alarm sound went off.
- What does this noise mean?
- I was driving at over 100 km/h (the speed limit on their highways at
that time). We have a warning system on all our cars.
- What about all those cars overtaking us? Do they produce the same noise?
- Yes.

This sound warning is optional on my car (i.e. can be disabled). The
visual warning (on the GPS display) however, is not.

From what I saw at that time, Japan was ridiculously underdeveloped on
some items (washing machines, squat toilets - well, they moved on in
these 40 years and we should learn a lot from them about modern toilets,
see <https://en.wikipedia.org/wiki/Toilets_in_Japan>), but it was much
better than Continental Europe on other items (bullet trains, fax etc.).
But even they did not have GPS displays 40 years ago.

I found that article on toilets in Japan to be interesting. I once
read a whole book about bathrooms, so it could be that I am easily
amused.

On my bucket-list; test-driving a Japanese-style
washlet toilet.

Must be the whole shebang with voice activated commands,
warm water bum wash and hot air dryer.

Janet

[Bertel Lund Hansen]

Post by Janet
On my bucket-list; test-driving a Japanese-style
washlet toilet.
Must be the whole shebang with voice activated commands,
warm water bum wash and hot air dryer.

Don't forget the music that prevents toilet sounds to be heard.

[occam]

Post by Janet

Post by Rich Ulrich
On Sat, 21 Sep 2024 21:11:31 +0200, Silvano

Post by Silvano

Post by occam

Post by Silvano
Japan was already wiser 40 years ago, but the more appropriate name is
probably "speed limit warnings".
A friend gave me a ride there when an alarm sound went off.
- What does this noise mean?
- I was driving at over 100 km/h (the speed limit on their highways at
that time). We have a warning system on all our cars.
- What about all those cars overtaking us? Do they produce the same noise?
- Yes.

This sound warning is optional on my car (i.e. can be disabled). The
visual warning (on the GPS display) however, is not.

From what I saw at that time, Japan was ridiculously underdeveloped on
some items (washing machines, squat toilets - well, they moved on in
these 40 years and we should learn a lot from them about modern toilets,
see <https://en.wikipedia.org/wiki/Toilets_in_Japan>), but it was much
better than Continental Europe on other items (bullet trains, fax etc.).
But even they did not have GPS displays 40 years ago.

I found that article on toilets in Japan to be interesting. I once
read a whole book about bathrooms, so it could be that I am easily
amused.

On my bucket-list; test-driving a Japanese-style
washlet toilet.
Must be the whole shebang with voice activated commands,
warm water bum wash and hot air dryer.

Have you started learning Japanese for the voice activation part? One
wrong intonation, and the seat may incinerate your privates.

[Silvano]

Post by occam

Post by Janet
On my bucket-list; test-driving a Japanese-style
washlet toilet.
Must be the whole shebang with voice activated commands,
warm water bum wash and hot air dryer.

Have you started learning Japanese for the voice activation part? One
wrong intonation, and the seat may incinerate your privates.

Just for your education, Japanese is NOT a tonal language. I do agree,
though, that you'd better learn the relevant ideograms before you use a
Japanese toilet, especially this one:
<Loading Image...>

Perhaps you're lucky and can use this one:
<Loading Image...>
I wonder what's the difference between shower and bidet here. Spray
height, as the picture suggests? I also wonder what you should do to
just flush your piss or poo.

[Janet]

Post by Silvano

Post by occam

Post by Janet
On my bucket-list; test-driving a Japanese-style
washlet toilet.
Must be the whole shebang with voice activated commands,
warm water bum wash and hot air dryer.

Have you started learning Japanese for the voice activation part? One
wrong intonation, and the seat may incinerate your privates.

Just for your education, Japanese is NOT a tonal language. I do agree,
though, that you'd better learn the relevant ideograms before you use a
<https://en.wikipedia.org/wiki/Toilets_in_Japan#/media/File:Wireless_toilet_control_panel_w._open_lid.jpg>
<https://en.wikipedia.org/wiki/Toilets_in_Japan#/media/File:Modern_japanese_toilet.jpg>
I wonder what's the difference between shower and bidet here. Spray
height, as the picture suggests?

I would think , spray direction. Front or back.

Janet

[Peter Moylan]

Post by Janet
On my bucket-list; test-driving a Japanese-style
washlet toilet.
Must be the whole shebang with voice activated commands,
warm water bum wash and hot air dryer.

I've just had a horrible thought. What if there are models that only
have cold water?

[Hibou]

Post by Aidan Kehoe

Post by Hibou
Our recent hire cars have displayed the speed limit, as read from limit
signs via their cameras. It is often wrong, displaying a recent speed
limit, not the current one - unsurprisingly, since in France there are a
variety of signs that set the speed (a crossed-out place name, for
instance), the camera lens may be dirty, a lorry may mask a sign, and so on.
Apparently, the crazy EU has made this flawed system the basis for
mandatory speed limiters (and the crazy UK has followed suit). If you
run into someone stuck at 30 kph on a 130 kph autoroute, that's probably
the reason.

A mandatory warning is part of the law, but actual restriction is not,

Do you have a source for that, a link?

Post by Aidan Kehoe
so
should you be in those occasional situations where breaking the speed limit is
safer than following it, you can (usually, depending on your manufacturer) just
keep the foot on the accelerator despite the alarm.

I think such situations are routine, not occasional.

Post by Aidan Kehoe

Post by Hibou
"However, our experience of such systems suggests they can get it wrong.
In one instance, a car's traffic sign recognition system picked up a
30mph sign on a turning off a dual carriage and dramatically slowed
down, despite the fact the car was actually travelling along the outside
lane" -
<https://www.parkers.co.uk/car-advice/speed-limiters-what-they-mean-for-you/>
God preserve us from government!

Apart from things like seatbelt laws, high taxes on tobacco, enforced rules on
food safety, regulation of medication? Or are you completely fine with easily
avoidable death and major disability, shorter and worse-quality lives, mass
poisonings, more mass poisonings? The middle option saves on taxes given if you
die at 63 from lung cancer you won’t draw much in the way of state pension, so
there is a financial but not humanitarian argument for it. There’s no argument
for the rest.

I think you've missed my point, which was that the system for
determining the speed limit is thoroughly unreliable, and not a suitable
basis for restrictors, or even alarms sounding in drivers' ears.


Let's explore a bit. To what extent should the state - or in the EU's
case the superstate - constrain people in order to make them safe?

A thought experiment. A parallel to inappropriate speed might be
inappropriate eating (I expect you know more about this than I).

"In the long-term, eating junk food can lead to: type 2 diabetes /
heart-related problems (such as cardiovascular disease, high blood
pressure and cholesterol) / overweight and obesity / osteoporosis /
certain cancers / depression /eating disorders / These complications are
all associated with a diet high in sugar, salt, trans- and saturated
fats and with a lack of essential nutrients like fibre, vitamins and
minerals" -
<https://www.healthdirect.gov.au/junk-food-and-your-health#complications>

Now, suppose it were possible to make an electronic implant that
monitored blood constituents, could detect when someone was digesting
junk food, and give that person a stomach ache.

Should the state force people to have that implant to save a proportion
of them from illness and premature death?

What if the implants' sensors were unreliable, and they often gave
people stomach aches even when they were eating healthily? Should the
state still make them mandatory?

[Hibou]

Post by Hibou
A thought experiment. A parallel to inappropriate speed might be
inappropriate eating (I expect you know more about this than I).

I mean you as a doctor, not as an eater.

[Aidan Kehoe]

Post by Hibou

Post by Hibou
A thought experiment. A parallel to inappropriate speed might be
inappropriate eating (I expect you know more about this than I).

I mean you as a doctor, not as an eater.

No offence taken!

[Aidan Kehoe]

Post by Hibou

Post by Aidan Kehoe

Post by Hibou
Our recent hire cars have displayed the speed limit, as read from limit
signs via their cameras. It is often wrong, displaying a recent speed
limit, not the current one - unsurprisingly, since in France there are a
variety of signs that set the speed (a crossed-out place name, for
instance), the camera lens may be dirty, a lorry may mask a sign, and so on.
Apparently, the crazy EU has made this flawed system the basis for
mandatory speed limiters (and the crazy UK has followed suit). If you
run into someone stuck at 30 kph on a 130 kph autoroute, that's probably
the reason.

A mandatory warning is part of the law, but actual restriction is not,

Do you have a source for that, a link?

https://etsc.eu/intelligent-speed-assistance-isa/

“The European Union agreed in 2019 to make an overridable version of
[intelligent speed assistance], along with a number of other vehicle safety
measures, mandatory on new models of car sold in the EU from July 2022 and on
all new cars sold from July 2024.”

Post by Hibou

Post by Aidan Kehoe
so should you be in those occasional situations where breaking the speed
limit is safer than following it, you can (usually, depending on your
manufacturer) just keep the foot on the accelerator despite the alarm.

I think such situations are routine, not occasional.

Post by Aidan Kehoe

Post by Hibou
"However, our experience of such systems suggests they can get it wrong.
In one instance, a car's traffic sign recognition system picked up a
30mph sign on a turning off a dual carriage and dramatically slowed
down, despite the fact the car was actually travelling along the outside
lane" -
<https://www.parkers.co.uk/car-advice/speed-limiters-what-they-mean-for-you/>
God preserve us from government!

Apart from things like seatbelt laws, high taxes on tobacco, enforced
rules on food safety, regulation of medication? Or are you completely fine
with easily avoidable death and major disability, shorter and
worse-quality lives, mass poisonings, more mass poisonings? The middle
option saves on taxes given if you die at 63 from lung cancer you won’t
draw much in the way of state pension, so there is a financial but not
humanitarian argument for it. There’s no argument for the rest.

I think you've missed my point, which was that the system for determining
the speed limit is thoroughly unreliable, and not a suitable basis for
restrictors, or even alarms sounding in drivers' ears.

Ah, maybe I have. My 2019 Toyota Corolla has a system that reads the
speed-limit signs, displays the currently active speed limit, and changes the
usual black-numbers-on-a-white-background display to
white-numbers-on-a-red-background if I exceed that speed. It very occasionally
gets things wrong but is usually reliable, even on those parts of the island
afflicted by speed limits in MPH. So my reading of things is from my own
relevant experience rather than a journalist driving clicks.

Post by Hibou
Let's explore a bit. To what extent should the state - or in the EU's case
the superstate - constrain people in order to make them safe?

It depends on the size of the safety benefit vs the tightness of the
constraint, and reasonable people can differ on where to make that trade-off,
which is why e.g. different jurisdictions have different drink-driving
thresholds.

Something the EU definitely gets wrong is banning anabolic steroids given to
livestock raised for slaughter, something that has been standard in the US for
decades without demonstrated ill-effect.

Post by Hibou
A thought experiment. A parallel to inappropriate speed might be
inappropriate eating (I expect you know more about this than I).
"In the long-term, eating junk food can lead to: type 2 diabetes /
heart-related problems (such as cardiovascular disease, high blood pressure
and cholesterol) / overweight and obesity / osteoporosis / certain cancers /
depression /eating disorders / These complications are all associated with a
diet high in sugar, salt, trans- and saturated fats and with a lack of
essential nutrients like fibre, vitamins and minerals" -
<https://www.healthdirect.gov.au/junk-food-and-your-health#complications>
Now, suppose it were possible to make an electronic implant that monitored
blood constituents, could detect when someone was digesting junk food, and
give that person a stomach ache.
Should the state force people to have that implant to save a proportion of
them from illness and premature death?

The state almost certainly shouldn’t be spending the money to implant this in
everyone, I’d rule it out for that reason. But on pure medical grounds, no,
people have a right to bodily autonomy, it is unethical to make such a thing
mandatory. If a life insurance company were to offer reduced premiums to people
willing to have such a sensor, that would be fine.

Post by Hibou
What if the implants' sensors were unreliable, and they often gave people
stomach aches even when they were eating healthily? Should the state still
make them mandatory?

[Peter Moylan]

Post by Aidan Kehoe

Post by Hibou
I think you've missed my point, which was that the system for
determining the speed limit is thoroughly unreliable, and not a
suitable basis for restrictors, or even alarms sounding in drivers'
ears.

Ah, maybe I have. My 2019 Toyota Corolla has a system that reads the
speed-limit signs, displays the currently active speed limit, and
changes the usual black-numbers-on-a-white-background display to
white-numbers-on-a-red-background if I exceed that speed. It very
occasionally gets things wrong but is usually reliable, even on those
parts of the island afflicted by speed limits in MPH. So my reading
of things is from my own relevant experience rather than a journalist
driving clicks.

My car, which is 14 years old, doesn't have such a feature. Despite that
my GPS navigator manages to display the speed limit, except in places
where reception from satellites is blocked. I assume that the limits are
contained in map data. Why then would the car need to read roadside signs?

OK, I'll concede that there are sometimes temporary limits in place
because of roadworks and so on, but that's the exceptional case.

[Snidely]

Post by Peter Moylan

Post by Aidan Kehoe

Post by Hibou
I think you've missed my point, which was that the system for
determining the speed limit is thoroughly unreliable, and not a
suitable basis for restrictors, or even alarms sounding in drivers'
ears.

Ah, maybe I have. My 2019 Toyota Corolla has a system that reads the
speed-limit signs, displays the currently active speed limit, and
changes the usual black-numbers-on-a-white-background display to
white-numbers-on-a-red-background if I exceed that speed. It very
occasionally gets things wrong but is usually reliable, even on those
parts of the island afflicted by speed limits in MPH. So my reading
of things is from my own relevant experience rather than a journalist
driving clicks.

My car, which is 14 years old, doesn't have such a feature. Despite that
my GPS navigator manages to display the speed limit, except in places
where reception from satellites is blocked. I assume that the limits are
contained in map data. Why then would the car need to read roadside signs?

Map data is often incomplete. I've had examples where my car has
displayed the wrong speed limit from map data, and then corrects it
when I manage to find a sign.

I've experienced very few errors with my car, the main examples being
school speed limits which are, per California law as related by the
driver's manual, only applicable when children are present on the
sidewalks and in the crosswalks around the school.

Post by Peter Moylan
OK, I'll concede that there are sometimes temporary limits in place
because of roadworks and so on, but that's the exceptional case.

Not at all exceptional in California on the freeways, although the
location changes from time to time.

/dps

[Aidan Kehoe]

Post by Peter Moylan

Post by Aidan Kehoe

Post by Hibou
I think you've missed my point, which was that the system for
determining the speed limit is thoroughly unreliable, and not a
suitable basis for restrictors, or even alarms sounding in drivers'
ears.

Ah, maybe I have. My 2019 Toyota Corolla has a system that reads the
speed-limit signs, displays the currently active speed limit, and
changes the usual black-numbers-on-a-white-background display to
white-numbers-on-a-red-background if I exceed that speed. It very
occasionally gets things wrong but is usually reliable, even on those
parts of the island afflicted by speed limits in MPH. So my reading
of things is from my own relevant experience rather than a journalist
driving clicks.

My car, which is 14 years old, doesn't have such a feature. Despite that
my GPS navigator manages to display the speed limit, except in places
where reception from satellites is blocked. I assume that the limits are
contained in map data. Why then would the car need to read roadside signs?

I was working on the assumption that the car does not have a GPS receiver; it
has a SIM card and will call the emergency services if it feels there is an
accident, and my working understanding was that its location sensing was done
in the same way that mobile phones do, with triangulation from masts.

However I have no mobile reception where I live and when I check today it does
seem to work out the location with reasonable fidelity (I don’t normallly use
the built-in navigation, Toyota do not excel at software) so it may have a
built-in GPS.

Post by Peter Moylan
OK, I'll concede that there are sometimes temporary limits in place
because of roadworks and so on, but that's the exceptional case.

It does pick up temporary speed limit signs that are unlikely to be in the map
data.

[Bertel Lund Hansen]

Post by Peter Moylan
My car, which is 14 years old, doesn't have such a feature. Despite that
my GPS navigator manages to display the speed limit, except in places
where reception from satellites is blocked. I assume that the limits are
contained in map data. Why then would the car need to read roadside signs?
OK, I'll concede that there are sometimes temporary limits in place
because of roadworks and so on, but that's the exceptional case.

It's not exceptional in Denmark. P.t. there are major repairs and
expansions on the motorways in Jutland. The won't be finished till 2026.

Okay, that's not everyday life, But I regularly see temporary speed
around road work.

Google Maps, which I use, is updated by user input and statistics, so it
takes some time until it gets it right.

Aside: GM has impressed me a couple of times. It gave me a route which
led to a road closed by road workers. A naive navigation would have
insisted on the same route, but when I turned the car around, GM gave me
another route that was open.

[Bertel Lund Hansen]

Post by Aidan Kehoe

Post by Hibou
Should the state force people to have that implant to save a proportion of
them from illness and premature death?

The state almost certainly shouldn’t be spending the money to implant this in
everyone, I’d rule it out for that reason. But on pure medical grounds, no,
people have a right to bodily autonomy, it is unethical to make such a thing
mandatory. If a life insurance company were to offer reduced premiums to people
willing to have such a sensor, that would be fine.

The comma after "no" is quite important. I missed it in my first reading
and got confused when I got to the text after the next comma.

My insurance company has given me the option to let them monitor my
driving which I accepted. If I drive carefully, the premium will be
reduced. I score 8 out of ten with my normal driving.

[Janet]

Post by Bertel Lund Hansen

Post by Hibou
Should the state force people to have that implant to save a proportion of
them from illness and premature death?

The state almost certainly shouldn?t be spending the money to implant this in
everyone, I?d rule it out for that reason. But on pure medical grounds, no,
people have a right to bodily autonomy, it is unethical to make such a thing
mandatory. If a life insurance company were to offer reduced premiums to people
willing to have such a sensor, that would be fine.

The comma after "no" is quite important. I missed it in my first reading
and got confused when I got to the text after the next comma.
My insurance company has given me the option to let them monitor my
driving which I accepted. If I drive carefully, the premium will be
reduced. I score 8 out of ten with my normal driving.

Excellent idea; one day all car insurers will work like
that.

Janet

[Sam Plusnet]

Post by Aidan Kehoe

Post by Hibou

Post by Aidan Kehoe

Post by Hibou
Our recent hire cars have displayed the speed limit, as read from limit
signs via their cameras. It is often wrong, displaying a recent speed
limit, not the current one - unsurprisingly, since in France there are a
variety of signs that set the speed (a crossed-out place name, for
instance), the camera lens may be dirty, a lorry may mask a sign, and so
on.
Apparently, the crazy EU has made this flawed system the basis for
mandatory speed limiters (and the crazy UK has followed suit). If you
run into someone stuck at 30 kph on a 130 kph autoroute, that's probably
the reason.

A mandatory warning is part of the law, but actual restriction is not,

Do you have a source for that, a link?

https://etsc.eu/intelligent-speed-assistance-isa/
“The European Union agreed in 2019 to make an overridable version of
[intelligent speed assistance], along with a number of other vehicle safety
measures, mandatory on new models of car sold in the EU from July 2022 and on
all new cars sold from July 2024.”

Post by Hibou

Post by Aidan Kehoe
so should you be in those occasional situations where breaking the speed
limit is safer than following it, you can (usually, depending on your
manufacturer) just keep the foot on the accelerator despite the alarm.

I think such situations are routine, not occasional.

Post by Aidan Kehoe

Post by Hibou
"However, our experience of such systems suggests they can get it wrong.
In one instance, a car's traffic sign recognition system picked up a
30mph sign on a turning off a dual carriage and dramatically slowed
down, despite the fact the car was actually travelling along the outside
lane" -
<https://www.parkers.co.uk/car-advice/speed-limiters-what-they-mean-for-you/>
God preserve us from government!

Apart from things like seatbelt laws, high taxes on tobacco, enforced
rules on food safety, regulation of medication? Or are you completely fine
with easily avoidable death and major disability, shorter and
worse-quality lives, mass poisonings, more mass poisonings? The middle
option saves on taxes given if you die at 63 from lung cancer you won’t
draw much in the way of state pension, so there is a financial but not
humanitarian argument for it. There’s no argument for the rest.

I think you've missed my point, which was that the system for determining
the speed limit is thoroughly unreliable, and not a suitable basis for
restrictors, or even alarms sounding in drivers' ears.

Ah, maybe I have. My 2019 Toyota Corolla has a system that reads the
speed-limit signs, displays the currently active speed limit, and changes the
usual black-numbers-on-a-white-background display to
white-numbers-on-a-red-background if I exceed that speed. It very occasionally
gets things wrong but is usually reliable, even on those parts of the island
afflicted by speed limits in MPH. So my reading of things is from my own
relevant experience rather than a journalist driving clicks.

This will be more of a problem for some, depending upon where you live.

My car uses a combination of satnav map data which includes the set
speed limit on each road, plus the output of the camera which (attempts
to) read speed limit signs.

Since the default speed limit in Wales was reduced to 20mph, the speed
limit displayed by my car has been wrong more often than it is
correct[1] - and not just reading "30" when it ought to be "20".

At the moment that is a nuisance.
If that same incorrect data is to be used in the way described in this
thread, it becomes far more than a nuisance.

[1] In a 8 mile radius around my home, I am not exaggerating when I say
"more often wrong that correct". - and yes the satnav's mapping data has
been updated twice in the year since the limit was changed.

[Aidan Kehoe]

Post by Sam Plusnet

Post by Aidan Kehoe
Ah, maybe I have. My 2019 Toyota Corolla has a system that reads the
speed-limit signs, displays the currently active speed limit, and changes
the usual black-numbers-on-a-white-background display to
white-numbers-on-a-red-background if I exceed that speed. It very
occasionally gets things wrong but is usually reliable, even on those
parts of the island afflicted by speed limits in MPH. So my reading of
things is from my own relevant experience rather than a journalist driving
clicks.

This will be more of a problem for some, depending upon where you live.
My car uses a combination of satnav map data which includes the set speed
limit on each road, plus the output of the camera which (attempts to) read
speed limit signs.
Since the default speed limit in Wales was reduced to 20mph, the speed limit
displayed by my car has been wrong more often than it is correct[1] - and not
just reading "30" when it ought to be "20".

That is very tedious, and a very different situation to mine.

Post by Sam Plusnet
At the moment that is a nuisance. If that same incorrect data is to be used
in the way described in this thread, it becomes far more than a nuisance.

No rush to buy a new car, then.

Post by Sam Plusnet
[1] In a 8 mile radius around my home, I am not exaggerating when I say
"more often wrong that correct". - and yes the satnav's mapping data has
been updated twice in the year since the limit was changed.

[Phil]

Post by Sam Plusnet

Post by Phil

Post by Bertel Lund Hansen

Post by Helmut Richter
And easier to remember than 1.609344. But when will you need such precision?
For instance, when you drive on German roads outside villages, you must
reduce your speed to 31.0685 mph whereas the rough rule 1 mi = 1.6 km would
have allowed you 31.2500 mph.

I haven't neede it, but just for fun I have calculated the Danish speed
         50 km = 30 mi
         80 km = 50 mi
       110 km = 70 mi (2 km too much)
       130 km = 80 mi

I'm not sure how common this is, but the speedometer in my car has
scales for both mph and km/h, so in principle I don't need to convert.
In practice, though, I have the above table in my head, from the old
days. It's easily remembered because the right-hand column corresponds
to the usual preferred values for UK speed limits.

Also, most modern cars can be persuaded to display speed (digitally) in
either mph or kph to suit your current needs.

Ah yes, I was forgetting just how old-school my car is -- it has an
actual needle moving on a circular scale.

[Bertel Lund Hansen]

Post by Phil
Ah yes, I was forgetting just how old-school my car is -- it has an
actual needle moving on a circular scale.

You mean "physical". My car has a virtual, oldfashioned speedometer, but
I always use the digital one. It's much nicer when I set the speed
limit.

[lar3ryca]

Post by Bertel Lund Hansen

Post by Helmut Richter
And easier to remember than 1.609344. But when will you need such precision?
For instance, when you drive on German roads outside villages, you must
reduce your speed to 31.0685 mph whereas the rough rule 1 mi = 1.6 km would
have allowed you 31.2500 mph.

I haven't neede it, but just for fun I have calculated the Danish speed
50 km = 30 mi
80 km = 50 mi
110 km = 70 mi (2 km too much)
130 km = 80 mi

'mi' should be 'MPH'.

I do pretty much mental conversions for distance, volume, weight, but I
have no use at all for metric area or pressure (to name just 2).
Almost nobody in these parts would speak to me in those terms, nor would
they know what magnitude I was speaking of.

[Peter Moylan]

Post by Helmut Richter
I like much more those thumb rules that actually allow you to estimate orders
1 year ≅ π · 10⁷ sec ≅ 31415926.54 sec
or
1 year ≅ √10 · 10⁷ sec ≅ 31622776.60 sec
or, only for those wanting more precision, the arithmetic mean of the two
which has three leading digits correct.

The one non-metric measurement that I find useful is "one foot per
nanosecond".

[J. J. Lodder]

Post by Peter Moylan

Post by Helmut Richter
I like much more those thumb rules that actually allow you to estimate
1 year ? π · 10? sec ? 31415926.54 sec
or
1 year ? √10 · 10? sec ? 31622776.60 sec
or, only for those wanting more precision, the arithmetic mean of the two
which has three leading digits correct.

The one non-metric measurement that I find useful is "one foot per
nanosecond".

Impossible to go that fast,

Jan

[Peter Moylan]

Post by J. J. Lodder

Post by Peter Moylan
The one non-metric measurement that I find useful is "one foot per
nanosecond".

Impossible to go that fast,

Useful, though, to get an estimate of the time delays across the width
of a printed circuit board.

I'm not actually involved in high-speed electronics, but I think the
current rule of thumb is that the speed of signals on a printed circuit
board is about two-thirds of the speed in a vacuum.

[J. J. Lodder]

Post by Helmut Richter

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.

... the English-speaking world with the exception of Ireland, Canada,
Australia, New Zealand, and South Africa and some others.
I think the term "United Kingdom and USA" would have been shorter and
slightly more accurate.

Post by Christian Weisgerber
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.
If nothing else, it's faster to type on a calculator.

And easier to remember than 1.609344. But when will you need such precision?
For instance, when you drive on German roads outside villages, you must
reduce your speed to 31.0685 mph whereas the rough rule 1 mi = 1.6 km would
have allowed you 31.2500 mph.
I like much more those thumb rules that actually allow you to estimate orders
1 year ? π · 10? sec ? 31415926.54 sec
or
1 year ? √10 · 10? sec ? 31622776.60 sec
or, only for those wanting more precision, the arithmetic mean of the two
which has three leading digits correct.

For orders of magitude there are 10^5 seconds to a day,
and 400 days to a year, so 40 million seconds to a year.
Both numbers are rounded up,
so the actual number is about 30 million seconds to a year.
All quite memorable.
The correct answer is 31 557 600 seconds/year (exactly)
so a quite acceptable estimate,

Jan

[charles]

Post by Helmut Richter

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict the
English-speaking world.

... the English-speaking world with the exception of Ireland, Canada,
Australia, New Zealand, and South Africa and some others.
I think the term "United Kingdom and USA" would have been shorter and
slightly more accurate.

Post by Christian Weisgerber
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits. If nothing else, it's
faster to type on a calculator.

And easier to remember than 1.609344. But when will you need such
precision? For instance, when you drive on German roads outside
villages, you must reduce your speed to 31.0685 mph whereas the rough
rule 1 mi = 1.6 km would have allowed you 31.2500 mph.
I like much more those thumb rules that actually allow you to estimate
1 year ? ð · 10? sec ? 31415926.54 sec
or
1 year ? #10 · 10? sec ? 31622776.60 sec
or, only for those wanting more precision, the arithmetic mean of the
two which has three leading digits correct.

For orders of magitude there are 10^5 seconds to a day, and 400 days to a
year, so 40 million seconds to a year. Both numbers are rounded up, so
the actual number is about 30 million seconds to a year. All quite
memorable. The correct answer is 31 557 600 seconds/year (exactly) so a
quite acceptable estimate,

I remember being told that a second is about a "micro-fortnight". Not very
accurate, but the right order of magnitude.

[Athel Cornish-Bowden]

Post by charles

Post by Helmut Richter

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict the
English-speaking world.

... the English-speaking world with the exception of Ireland, Canada,
Australia, New Zealand, and South Africa and some others.
I think the term "United Kingdom and USA" would have been shorter and
slightly more accurate.

Post by Christian Weisgerber
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits. If nothing else, it's
faster to type on a calculator.

And easier to remember than 1.609344. But when will you need such
precision? For instance, when you drive on German roads outside
villages, you must reduce your speed to 31.0685 mph whereas the rough
rule 1 mi = 1.6 km would have allowed you 31.2500 mph.
I like much more those thumb rules that actually allow you to estimate
1 year ? ð · 10? sec ? 31415926.54 sec
or
1 year ? #10 · 10? sec ? 31622776.60 sec
or, only for those wanting more precision, the arithmetic mean of the
two which has three leading digits correct.

For orders of magitude there are 10^5 seconds to a day, and 400 days to a
year, so 40 million seconds to a year. Both numbers are rounded up, so
the actual number is about 30 million seconds to a year. All quite
memorable. The correct answer is 31 557 600 seconds/year (exactly) so a
quite acceptable estimate,

I remember being told that a second is about a "micro-fortnight". Not very
accurate, but the right order of magnitude.

I knew someone who liked to start his seminars with a statement that he
would talk for a microcentury, to allow time for questions and
discussion.

[Steve Hayes]

On Sat, 21 Sep 2024 10:59:18 +0200, Athel Cornish-Bowden

Post by Athel Cornish-Bowden
I knew someone who liked to start his seminars with a statement that he
would talk for a microcentury, to allow time for questions and
discussion.

+1

[J. J. Lodder]

Post by Steve Hayes
On Sat, 21 Sep 2024 10:59:18 +0200, Athel Cornish-Bowden

Post by Athel Cornish-Bowden
I knew someone who liked to start his seminars with a statement that he
would talk for a microcentury, to allow time for questions and
discussion.

+1

One of those stale jokes, by now old enough
for the originator to haven been forgotten,

Jan

[Athel Cornish-Bowden]

Post by J. J. Lodder

Post by Steve Hayes
On Sat, 21 Sep 2024 10:59:18 +0200, Athel Cornish-Bowden

Post by Athel Cornish-Bowden
I knew someone who liked to start his seminars with a statement that he
would talk for a microcentury, to allow time for questions and
discussion.

+1

One of those stale jokes, by now old enough
for the originator to haven been forgotten,

No doubt stale for physicists, but my informant was used to addressing
audiences of biochemists, who were usually unfamiliar with the idea.

[Christian Weisgerber]

Post by Helmut Richter

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.

... the English-speaking world with the exception of Ireland, Canada,
Australia, New Zealand, and South Africa and some others.

I'm well aware, but they still suffer exposure by way of American
media.

The American-Canadian border in particular is very leaky in this
regard. Canada is notionally fully metric, but economically aligned
with the US, and in practice you can find American units even in
Canadian French.

[jerryfriedman]

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.
If nothing else, it's faster to type on a calculator.
I think that's hysterical.

Hey, that's closer than the golden ratio.

I only know log(5) = about 1.6 because my graduate adviser
suggested I learn log(2) = 0.7, log(3) = 1.1, log(7) = 2, and
log(20) = 3. It was handy for what I was doing.

--
Jerry Friedman

[Rich Ulrich]

Post by jerryfriedman

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.
If nothing else, it's faster to type on a calculator.
I think that's hysterical.

Hey, that's closer than the golden ratio.
I only know log(5) = about 1.6 because my graduate adviser
suggested I learn log(2) = 0.7, log(3) = 1.1, log(7) = 2, and
log(20) = 3. It was handy for what I was doing.

It bothers me to see log(x) written for the 'natural log' --

Somewhere, some time, I learned to write ln(X) for the
natural log, log(X) for log_10 or whenever it does not matter.

But I realize that it is a long time since I've read stuff where
it matters. I wonder whether my convention, writing ln(X), was
ever widespread.

[Stefan Ram]

Post by Rich Ulrich
But I realize that it is a long time since I've read stuff where
it matters. I wonder whether my convention, writing ln(X), was
ever widespread.

Yeah, I totally had the same experience in school back in the day.

The "newer" convention rings a bell from programming languages like
C and Python. The thinking behind it is probably that the natural
log has the best claim to being THE log, hands down.

[jerryfriedman]

Post by Stefan Ram

Post by Rich Ulrich
But I realize that it is a long time since I've read stuff where
it matters. I wonder whether my convention, writing ln(X), was
ever widespread.

Yeah, I totally had the same experience in school back in the day.

I learned ln in school too, and I teach it to my students.
But once I got past high school calculus, "log" was always
the natural log, and others were hardly if ever mentioned.

Post by Stefan Ram
The "newer" convention rings a bell from programming languages like
C and Python. The thinking behind it is probably that the natural
log has the best claim to being THE log, hands down.

The thinking is correct, though a bit understated.

--
Jerry Friedman

[Garrett Wollman]

Post by Stefan Ram
The "newer" convention rings a bell from programming languages like
C and Python. The thinking behind it is probably that the natural
log has the best claim to being THE log, hands down.

Many engineers are likely to be baffled by such a statement, since
they work in base-10 logarithms all the time, and never use natural
log for anything. Notably, the Bel is a base-10 logarithm, so every
acoustic, broadcasting, electrical or electronic engineer knows that
10 log(2) is about 3.02 (or just 3 for short, the 0.46% difference
isn't big enough to matter), just as they know that sqrt(10) is about
3.16 -- these numbers show up everywhere.[1]

-GAWollman

[1] Don't get me started on the crazy distinction between decibel
power and decibel amplitude, and yes I know why they're different.

[J. J. Lodder]

Post by Garrett Wollman

Post by Stefan Ram
The "newer" convention rings a bell from programming languages like
C and Python. The thinking behind it is probably that the natural
log has the best claim to being THE log, hands down.

Many engineers are likely to be baffled by such a statement, since
they work in base-10 logarithms all the time, and never use natural
log for anything. Notably, the Bel is a base-10 logarithm, so every
acoustic, broadcasting, electrical or electronic engineer knows that
10 log(2) is about 3.02 (or just 3 for short, the 0.46% difference
isn't big enough to matter), just as they know that sqrt(10) is about
3.16 -- these numbers show up everywhere.[1]
-GAWollman
[1] Don't get me started on the crazy distinction between decibel
power and decibel amplitude, and yes I know why they're different.

Many engineers live in an impoverished world
where only multiplications matter.
Hence their historical attachment to their slide rules,

Jan

[Peter Moylan]

Post by Garrett Wollman

Post by Stefan Ram
The "newer" convention rings a bell from programming languages
like C and Python. The thinking behind it is probably that the
natural log has the best claim to being THE log, hands down.

Many engineers are likely to be baffled by such a statement, since
they work in base-10 logarithms all the time, and never use
natural log for anything. Notably, the Bel is a base-10 logarithm,
so every acoustic, broadcasting, electrical or electronic engineer
knows that 10 log(2) is about 3.02 (or just 3 for short, the 0.46%
difference isn't big enough to matter), just as they know that
sqrt(10) is about 3.16 -- these numbers show up everywhere.[1]
-GAWollman
[1] Don't get me started on the crazy distinction between decibel
power and decibel amplitude, and yes I know why they're different.

Many engineers live in an impoverished world where only
multiplications matter. Hence their historical attachment to their
slide rules,

Impoverishment is in the eye of the beholder.

All electrical engineers learn why the gain of amplifiers, beyond
the stopband, decays at a rate of 20 dB/decade, or at integer multiples
of that, and most could probably explain the mathematics of it.
(Although the explanation might end up assuming that you understand
concepts that you haven't yet encountered.) Is that piece of magic known
to other people? I have sometimes wondered.

[J. J. Lodder]

Post by Peter Moylan

Post by Garrett Wollman

Post by Stefan Ram
The "newer" convention rings a bell from programming languages
like C and Python. The thinking behind it is probably that the
natural log has the best claim to being THE log, hands down.

Many engineers are likely to be baffled by such a statement, since
they work in base-10 logarithms all the time, and never use
natural log for anything. Notably, the Bel is a base-10 logarithm,
so every acoustic, broadcasting, electrical or electronic engineer
knows that 10 log(2) is about 3.02 (or just 3 for short, the 0.46%
difference isn't big enough to matter), just as they know that
sqrt(10) is about 3.16 -- these numbers show up everywhere.[1]
-GAWollman
[1] Don't get me started on the crazy distinction between decibel
power and decibel amplitude, and yes I know why they're different.

Many engineers live in an impoverished world where only
multiplications matter. Hence their historical attachment to their
slide rules,

Impoverishment is in the eye of the beholder.
All electrical engineers learn why the gain of amplifiers, beyond
the stopband, decays at a rate of 20 dB/decade, or at integer multiples
of that, and most could probably explain the mathematics of it.
(Although the explanation might end up assuming that you understand
concepts that you haven't yet encountered.) Is that piece of magic known
to other people? I have sometimes wondered.

That's for tone deaf engineers.
People with a musical sense will know that it is 6dB/octave,

Jan

[Bertel Lund Hansen]

Post by J. J. Lodder
Many engineers live in an impoverished world
where only multiplications matter.
Hence their historical attachment to their slide rules,

Well, in all fairness: They have done pretty well with it, haven't they?

(Written by the son of an engineer who is fond of his traditional tools)

[J. J. Lodder]

Post by Bertel Lund Hansen

Post by J. J. Lodder
Many engineers live in an impoverished world
where only multiplications matter.
Hence their historical attachment to their slide rules,

Well, in all fairness: They have done pretty well with it, haven't they?
(Written by the son of an engineer who is fond of his traditional tools)

No better than a centibell,

Jan

[Bertel Lund Hansen]

Post by Rich Ulrich

Post by jerryfriedman
I only know log(5) = about 1.6 because my graduate adviser
suggested I learn log(2) = 0.7, log(3) = 1.1, log(7) = 2, and
log(20) = 3. It was handy for what I was doing.

It bothers me to see log(x) written for the 'natural log' --

Ditto. Unfortunately Python makes the same mistake.

Post by Rich Ulrich
Somewhere, some time, I learned to write ln(X) for the
natural log, log(X) for log_10 or whenever it does not matter.
But I realize that it is a long time since I've read stuff where
it matters. I wonder whether my convention, writing ln(X), was
ever widespread.

That's what we learned in high school in math.

[Athel Cornish-Bowden]

Post by Bertel Lund Hansen

Post by Rich Ulrich

Post by jerryfriedman
I only know log(5) = about 1.6 because my graduate adviser
suggested I learn log(2) = 0.7, log(3) = 1.1, log(7) = 2, and
log(20) = 3. It was handy for what I was doing.

It bothers me to see log(x) written for the 'natural log' --

Ditto. Unfortunately Python makes the same mistake.

I think Pascal does the same. If you want "common" logarithms you need log10.

Microbiologists who study bacterial growth use log_2, but I don't know
of a language that allows for that.

Post by Bertel Lund Hansen

Post by Rich Ulrich
Somewhere, some time, I learned to write ln(X) for the
natural log, log(X) for log_10 or whenever it does not matter.
But I realize that it is a long time since I've read stuff where
it matters. I wonder whether my convention, writing ln(X), was
ever widespread.

That's what we learned in high school in math.

[Bertel Lund Hansen]

Post by Athel Cornish-Bowden

Post by Bertel Lund Hansen

Post by Rich Ulrich
It bothers me to see log(x) written for the 'natural log' --

Ditto. Unfortunately Python makes the same mistake.

I think Pascal does the same. If you want "common" logarithms you need log10.
Microbiologists who study bacterial growth use log_2, but I don't know
of a language that allows for that.

Post by Bertel Lund Hansen

Post by Rich Ulrich
math.log2(100)

6.643856189774724

I tried other digits, but they don't work.

[Aidan Kehoe]

Post by Athel Cornish-Bowden

Post by Bertel Lund Hansen

Post by Rich Ulrich

Post by jerryfriedman
I only know log(5) = about 1.6 because my graduate adviser
suggested I learn log(2) = 0.7, log(3) = 1.1, log(7) = 2, and
log(20) = 3. It was handy for what I was doing.

It bothers me to see log(x) written for the 'natural log' --

Ditto. Unfortunately Python makes the same mistake.

I think Pascal does the same. If you want "common" logarithms you need log10.
Microbiologists who study bacterial growth use log_2, but I don't know of a
language that allows for that.

A floating-point log2() is in C99 and for integers bit manipulation is
generally good enough in any language that supports bit manipulation.

[Snidely]

Post by Bertel Lund Hansen

Post by Rich Ulrich

Post by jerryfriedman
I only know log(5) = about 1.6 because my graduate adviser
suggested I learn log(2) = 0.7, log(3) = 1.1, log(7) = 2, and
log(20) = 3. It was handy for what I was doing.

It bothers me to see log(x) written for the 'natural log' --

Ditto. Unfortunately Python makes the same mistake.

Post by Rich Ulrich
Somewhere, some time, I learned to write ln(X) for the
natural log, log(X) for log_10 or whenever it does not matter.
But I realize that it is a long time since I've read stuff where
it matters. I wonder whether my convention, writing ln(X), was
ever widespread.

That's what we learned in high school in math.

ditto

-d

[Garrett Wollman]

Post by Rich Ulrich
Somewhere, some time, I learned to write ln(X) for the
natural log, log(X) for log_10 or whenever it does not matter.

That's what I learned as well, and indeed that is what the labels on
my HP48 scientific calculator say, too.

-GAWollman

[Bertel Lund Hansen]

Post by Garrett Wollman

Post by Rich Ulrich
Somewhere, some time, I learned to write ln(X) for the
natural log, log(X) for log_10 or whenever it does not matter.

That's what I learned as well, and indeed that is what the labels on
my HP48 scientific calculator say, too.

My Texas TI-89 does the same.

[Rich Ulrich]

On Fri, 20 Sep 2024 21:50:55 +0200, Bertel Lund Hansen

Post by Bertel Lund Hansen

Post by Garrett Wollman

Post by Rich Ulrich
Somewhere, some time, I learned to write ln(X) for the
natural log, log(X) for log_10 or whenever it does not matter.

That's what I learned as well, and indeed that is what the labels on
my HP48 scientific calculator say, too.

My Texas TI-89 does the same.

My Sharp EL-5813 does the same.

I notice that e^^X and ln(X) are primary, and 10^^X and log(X)
are secondary functions for the two respective keys.

[Peter Moylan]

Post by Rich Ulrich
On Fri, 20 Sep 2024 21:50:55 +0200, Bertel Lund Hansen

Post by Bertel Lund Hansen

Post by Garrett Wollman

Post by Rich Ulrich
Somewhere, some time, I learned to write ln(X) for the
natural log, log(X) for log_10 or whenever it does not matter.

That's what I learned as well, and indeed that is what the labels on
my HP48 scientific calculator say, too.

My Texas TI-89 does the same.

My Sharp EL-5813 does the same.
I notice that e^^X and ln(X) are primary, and 10^^X and log(X)
are secondary functions for the two respective keys.

For what it's worth, the software calculator I wrote myself has
functions ln and log10.

[Peter Moylan]

Post by Peter Moylan

Post by Rich Ulrich
On Fri, 20 Sep 2024 21:50:55 +0200, Bertel Lund Hansen

Post by Bertel Lund Hansen

Post by Garrett Wollman

Post by Rich Ulrich
Somewhere, some time, I learned to write ln(X) for the
natural log, log(X) for log_10 or whenever it does not
matter.

That's what I learned as well, and indeed that is what the
labels on my HP48 scientific calculator say, too.

My Texas TI-89 does the same.

My Sharp EL-5813 does the same.
I notice that e^^X and ln(X) are primary, and 10^^X and log(X)
are secondary functions for the two respective keys.

For what it's worth, the software calculator I wrote myself has
functions ln and log10.

The part I forgot to add: as evidence, this is of course only evidence
of my opinion. That opinion was, however, formed after taking a good
look at what standard practice seemed to be. I wanted to produce the
best calculator among the OS/2 offerings, so I took care to get it right.

[Hibou]

Post by Rich Ulrich

Post by Bertel Lund Hansen
[...]

Post by Garrett Wollman

Post by Rich Ulrich
Somewhere, some time, I learned to write ln(X) for the
natural log, log(X) for log_10 or whenever it does not matter.

That's what I learned as well, and indeed that is what the labels on
my HP48 scientific calculator say, too.

My Texas TI-89 does the same.

My Sharp EL-5813 does the same.
I notice that e^^X and ln(X) are primary,

Seems reasonable. e is wired into the Universe; 10 is just the number of
fingers possessed by a biological growth on an obscure planet.

Post by Rich Ulrich
and 10^^X and log(X)
are secondary functions for the two respective keys.

[J. J. Lodder]

Post by Rich Ulrich

Post by jerryfriedman

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.
If nothing else, it's faster to type on a calculator.
I think that's hysterical.

Hey, that's closer than the golden ratio.
I only know log(5) = about 1.6 because my graduate adviser
suggested I learn log(2) = 0.7, log(3) = 1.1, log(7) = 2, and
log(20) = 3. It was handy for what I was doing.

It bothers me to see log(x) written for the 'natural log' --
Somewhere, some time, I learned to write ln(X) for the
natural log, log(X) for log_10 or whenever it does not matter.
But I realize that it is a long time since I've read stuff where
it matters. I wonder whether my convention, writing ln(X), was
ever widespread.

Only among the number pushers.
Real mathematicians and scientists usually didn't bother,
and just wrote and said log,

Jan

[kami]

On Thu, 19 Sep 2024 23:12:52 -0000 (UTC), Christian Weisgerber

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.
If nothing else, it's faster to type on a calculator.
I think that's hysterical.

simplest method is to multiply by 0.6

[Snidely]

Post by kami
On Thu, 19 Sep 2024 23:12:52 -0000 (UTC), Christian Weisgerber

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.
If nothing else, it's faster to type on a calculator.
I think that's hysterical.

simplest method is to multiply by 0.6

There's no humor in that.

-d

[kami]

Post by Snidely

Post by kami
On Thu, 19 Sep 2024 23:12:52 -0000 (UTC), Christian Weisgerber

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.
If nothing else, it's faster to type on a calculator.
I think that's hysterical.

simplest method is to multiply by 0.6

There's no humor in that.
-d

an easier method would be, if the limit is 80 miles per hour,
simply add half, which is 40 and then one tenth of that, which is
4 and multiply it by 2 which is 8, so 48 + 80 is 128 km/h

similarly lets say 120 miles per hour, half 60, tenth times 2 is
12, so 72 + 120 = 192 km/h.

[Snidely]

On Sunday, kami pointed out that ...

Post by kami

Post by Snidely

Post by kami
On Thu, 19 Sep 2024 23:12:52 -0000 (UTC), Christian Weisgerber

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.
If nothing else, it's faster to type on a calculator.
I think that's hysterical.

simplest method is to multiply by 0.6

There's no humor in that.
-d

an easier method would be, if the limit is 80 miles per hour,
simply add half, which is 40 and then one tenth of that, which is
4 and multiply it by 2 which is 8, so 48 + 80 is 128 km/h
similarly lets say 120 miles per hour, half 60, tenth times 2 is
12, so 72 + 120 = 192 km/h.

There's no humor in that.

-d

[Kerr-Mudd, John]

On Sun, 22 Sep 2024 03:19:42 -0700

Post by Snidely
On Sunday, kami pointed out that ...

Post by kami

Post by Snidely

Post by kami
On Thu, 19 Sep 2024 23:12:52 -0000 (UTC), Christian Weisgerber

Post by Christian Weisgerber
I'm sorry, I don't know where to post this. I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.
So you want to convert between miles and kilometers. The conversion
factor is... uh... A 40-year-old calculator book provides a useful
tip: Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers. It's accurate to four digits.
If nothing else, it's faster to type on a calculator.
I think that's hysterical.

simplest method is to multiply by 0.6

There's no humor in that.
-d

an easier method would be, if the limit is 80 miles per hour,
simply add half, which is 40 and then one tenth of that, which is
4 and multiply it by 2 which is 8, so 48 + 80 is 128 km/h
similarly lets say 120 miles per hour, half 60, tenth times 2 is
12, so 72 + 120 = 192 km/h.

Sounds illegal to me.

70mph is the max in the UK, but only on motorways and dual carriageways (as
we so quaintly call them) - this means that the traffic in opposite
directions has a barrier between it, not as some naively think, that the
road has 2 or more lanes in the same direction).

A supermarket car park near me has 5mph signs; I've never seen any vehicle
travel that slow, unless manoeuvring into a slot.

Post by Snidely
There's no humor in that.

isn't there? if 0.6 is right then pshurely you want to add a half and a
tenth.

Or memorise a table:
(80) 130
(75) 120
70+35+7=112(110)
60+30+6= 96(100)
(55) 90
50+25+5= 80 80
(45) 70
40+20+4= 64 (60)
(35) 50
30+15+3= 38 (40)
20+10+2= 32 (30)

[Bertel Lund Hansen]

Post by Kerr-Mudd, John
A supermarket car park near me has 5mph signs; I've never seen any vehicle
travel that slow, unless manoeuvring into a slot.

My local reuse dump has a 15 kph limit. I find it ridiculous to drive
that slow. I go about 20-25 kph. But beforre the final bump I drive
maybe 3 kph. Otherwise it's uncomfortable. Inside the dump where people
drive and walk, I drive very slowly.

[Phil]

Post by Snidely
On Sunday, kami pointed out that ...

Post by kami

Post by Snidely

Post by kami
On Thu, 19 Sep 2024 23:12:52 -0000 (UTC), Christian Weisgerber

I'm sorry, I don't know where to post this.  I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.
So you want to convert between miles and kilometers.  The conversion
factor is... uh...  A 40-year-old calculator book provides a useful
tip:  Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers.  It's accurate to four digits.
If nothing else, it's faster to type on a calculator.
I think that's hysterical.

simplest method is to multiply by 0.6

There's no humor in that.
-d

an easier method would be, if the limit is 80 miles per hour,
simply add half, which is 40 and then one tenth of that, which is
4 and multiply it by 2 which is 8, so 48 + 80 is 128 km/h
similarly lets say 120 miles per hour, half 60, tenth times 2 is
12, so 72 + 120 = 192 km/h.

There's no humor in that.
-d

<Loading Image...>

[Snidely]

Post by Phil

Post by Snidely
On Sunday, kami pointed out that ...

Post by kami

Post by Snidely

Post by kami
On Thu, 19 Sep 2024 23:12:52 -0000 (UTC), Christian Weisgerber

I'm sorry, I don't know where to post this.  I'm crossposting to
alt.usage.english, because statute miles as a unit mostly afflict
the English-speaking world.
So you want to convert between miles and kilometers.  The conversion
factor is... uh...  A 40-year-old calculator book provides a useful
tip:  Unless you're designing a space probe, you can use ln(5).
WHAT?
Yes, the natural logrithm of 5 approximates the conversion factor
between miles and kilometers; specifically one mile is about ln(5)
kilometers.  It's accurate to four digits.
If nothing else, it's faster to type on a calculator.
I think that's hysterical.

simplest method is to multiply by 0.6

There's no humor in that.
-d

an easier method would be, if the limit is 80 miles per hour,
simply add half, which is 40 and then one tenth of that, which is
4 and multiply it by 2 which is 8, so 48 + 80 is 128 km/h
similarly lets say 120 miles per hour, half 60, tenth times 2 is
12, so 72 + 120 = 192 km/h.

There's no humor in that.
-d

<https://wesharman.wordpress.com/wp-content/uploads/2013/11/4525f-bkliban001.jpg>

That's a bit better.

-d

[Bertel Lund Hansen]

Post by kami
an easier method would be, if the limit is 80 miles per hour,
simply add half, which is 40 and then one tenth of that, which is
4 and multiply it by 2 which is 8, so 48 + 80 is 128 km/h

I find it easier to multiply by 1.6.

I once gave one of my pupils less than maximum for an answer. The
problem demanded that you do the math approximately. He had calculated
the precise answer in his head and clamid that it was just as quick
(which it was for him). He was displeased with my scoring.