Re:Show HN: Long Range E-Bike
by leetcrew on Friday November 12, 2021 @02:31PM
(#29203552)
that equation shows velocity is more important though? a small car at 10 mph has about the same KE as a 200 lb person going 40 mph. of course KE doesn't tell the whole story. of the two, I'd much rather be hit by the car. I could run into a brick wall at 10 mph and probably be okay.
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I suppose if you absorbed all of the energy from the car, rather than just being pushed back by it, then the damage might be more comparable. For example, I think if someone was standing against a wall and a car rolled into them at 10mpg it might be as terrible as being hit by a 200lb cyclist at 40 mph. Of course, I agree that 10 mph seems a lot less dangerous - it gives many more options to move out of the way, or to spread the impact over time (by walking backwards and pushing against the car). Just throwing out some thoughts on why the same energy from each seems to have such a different destructive force.
Re:Show HN: Long Range E-Bike
by frenchyatwork on Friday November 12, 2021 @04:18PM
(#29204646)
True, though most collisions aren't head on, and even when they are, usually only a fraction of the velocity is absorbed because the objects deflect from each other.