> Cars are structurally complex. Just consider rubber balls of equal size and > use their deformation as a measure of "damage". If the two rubber balls > move towards each other they will deform an equal amount when they collide. > If one rubber ball is resting against a massive wall and the other rubber > ball runs into it will they experience the same deformation? >
..the point was, which collision would you rather be in - which'll dissipate the most energy, given that the collision speed is identical in both cases? The intention was to prompt one to calculate that the KE's are calculated relative to the inertial FoR of the ground / planet, not one another.. ..thus colliding one rubber ball with the wall at say 2 m/s dissipates 4x as much energy as either ball colliding head-on at 1 m/s.. ..and still twice as much as that of both balls together. In short, because energy squares with velocity relative to the ground (not one another), 2x the absolute speed = 4x the energy. The intent is to illustrate the dependence of CoE upon CoM and inertial FoR's tho..
