I was bored just there, and so sat and worked out kinetic energy for car +
driver as opposed to cycle + rider. The formula being 1/2 mv2 (can't do
superscript in ASCII), take a 1,500 kg car travelling at 30 mph. Take a
100 kg bicycle with rider. At what speed would the cyclist have to ride,
to have the same kinetic energy as a car? And of course, 'show your work'.
1/2 mv2 --> 1/2 1500 kg x 13.4 m/s2 == 134,670 joules
Then ..
134,670 joules = 1/2 100 kg * ? m/s2
An easier way would of course be:
mv2
------- = KE * 2
2
So the answer is 51.89 metres per second, which is around 116 mph. I
know that force and kinetic energy are not the same, but 'vulgarised': a
cyclist would have to be cycling at one hundred and sixteen miles per hour,
to generate the same kinetic energy as a 1.5 tonne car at thirty miles per
hour. And a lot of cars are heavier than that. The penis substitute
from Audi, for example - that big 'SUV' - comes in at 2,445 kg. Let's add
two people at 80 kg each, and a half tank of petrol - I think their fuel
tanks are about 75 litres, so let's go with 37 litres, which will weigh
around 28 kg). So we have a car weighing 2,633 kg. Let's go with 30 mph.
The same formula ..
1/2 mv2 --> 1/2 2633 * 13.4 m/s2 == 236,390 joules.
To generate the same kinetic energy, our trusty 100 kg cyclist would need
to be cycling at ...
236,390 = 1/2 100 kg * ? m/s2
.. or 68 metres per second. What's that in mph? A very handy 152 mph.
The land speed record on a bicycle would appear to be 207.9 mph, which was
on a treadmill, but the actual flat surface, 'motor-paced' record is 167
mph. Put another way, rich, self-entitled businessman in his Audi SUV
complains that 30 mph is 'too slow for modern cars', whilst complaining
that cyclists are 'a menace'. I wonder how many of these 'menacing'
cyclists he sees going at 150 mph on his daily commute from Chelsea to the
Square Mile.
But let's go with the 'average' car. One hundred and sixteen miles per
hour. How many cyclists have you seen at that speed? Yet that is
considered 'slow' for a car, and many car drivers bleat if they get a
ticket by exceeding that speed. Funny that, isn't it? A cyclist at 20 mph
is 'speeding', yet a car driver at 30 mph is 'being unfairly restricted'.
Let's say the car you saw had just started off and was at 10 mph. 10 mph
is 4.47 m/s so we get..
1/2 mv2 --> 1/2 1500 kg x 4.47 m/s2 == 14,985 joules.
So..
14,985 joules = 1/2 100 kg * ? ms/2
And that gives us .. 17.1 m/s or roughly 38.2 mph.
Now, I'm a pretty strong cyclist, and I just checked my stats from the last
month commuting, and my top speed on a very steep hill is 36 mph and my
average speed over the ten miles (when I take the long route) to work
varies between 14.8 mph and 19 mph. On the flat, I tend to 'peak' at 25
to 30 mph and at my age, can't really hold that for more than a couple of
minutes. And the faster speeds are when I'm rested, have had a day or two
off the bike, and haven't drunk too much the night before.
Your claim is that you are often placed in more danger by a cyclist 'at
speed' going through a red light, than by a car whose driver has just
started to accelerate. How many of those cyclists are going faster than 40
mph when they 'almost hit you'?
I'm willing to bet that the answer is 'none'.
And my experience of car drivers in the UK, in France and here in Israel is
that when they're coming up to a set of traffic lights and those lights go
to amber or red (here, they flash before becoming red) is that they put the
foot down. Matey in his Audi screams through the lights at 30 mph, and
hits a pedestrian. Oh no! Cries the pedestrian! Just as well I didn't get
hit by a cyclist, 'cos he's much more dangerous to me! I mean, every
second cyclist goes through these fucking lights at a hundred and fifty
miles an hour!
No. I don't think so.
Y.
--
Yitzhak Isaac Goldstein
'No amount of cajolery can eradicate from my heart a deep burning
hatred for the Tory Party. They are lower than vermin'.
(Aneurin Bevan (1897 - 1960))
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