Originally Posted by
Amitoj
Since kinetic energy and momentum have a direct linear relationship (k.e. = (1/2)m*v*v), a heavier object will transfer more energy to the cyclist than a lighter one, which wont be too kind to our bones, joints and internal organs. This is also the reason why a heavier bat does not need to be swung very fast to dispatch a ball to the boundary in cricket.
Right. I think the problem with the intuitive approach here is that people don't have enough experience with getting hit by very heavy objects to grasp this intuitively and if they have, they probably didn't survive it.
I also think it's an artifact of how we look at the regulatory problem. We're used to speed limits, so if you're going to argue for a lower one, you'll probably plug in a number for average vehicle weight just to show how differences in v-squared are huge with just a 10 mph reduction in speed. We probably don't do the calculation for different vehicle weights because we really aren't used to the concept of regulating vehicle size except on bridges and the like. When you multiply that linear weight difference by v-squared, you get dramatically different figures for the effectiveness of that 10 mph reduction in absolute terms.
And we haven't even touched on the obvious implications of increased kinetic energy on braking distances.