Consider two less$-$than$-$desirable options. In the first you are driving $30$ mph and crash head$-$on into an identical car also going $30$ mph$.$ In the second option you are driving $30$ mph and crash head$-$on into a stationary brick wall. In neither case does your car bounce back from the thing it hits, and the collision time is the same in both cases. Which of these two situations would result