>>>>Here's something to make you think about speeding.
>>>>
>>>>120mph crash test
>>>>
>>>>http://www.youtube.com/watch?v=6dI5ewOmHPQ&feature=player_embedded#!
>>>
>>>Their logic seems a bit wonky. One car hitting a wall at 120 is not the same as two cars hitting each other head on at 120. Wouldn't the car have to do 240 to simulate that ?
>>
>>No. 1 car hitting an immovable object at 120 takes the full force, however, 2 cars travelling at 120 (assuming similar mass) would disperse the force equally between them, thus they would both take the equilivent of hitting the wall at 120 not 240.
>
>That's correct, although in engineering parlance you're talking about "energy" (kinetic) rather than "force".

Oops, I originally had a more lengthy explanation which I edited down, apparently not well enough. ;)

Thanks for the correction.

>It's worth noting that energy varies as the *square* of velocity, so a car hitting the concrete block at 120mph absorbs 4x the energy of one traveling at 60mph.
>
>>
>>>In practice I'd guess a combined impact speed of 120 is *very* rare. Usually one or both drivers has braked pretty hard before the impact - the 40 mph test is probably a truer reflection of what happens in reality....

6dI5ewOmHPQ