1. The problem statement, all variables and given/known data A little ball bounces straight on a surface in a certain way so that at every bounce it loses a fraction of it's vertical speed (called e in this equation). Assume that the ball is released from a ''resting height' (called H in this equation). Show that after the n'th bounce against the surface the ball has reached: [itex]H_n=e^2n * H [/itex] 2. Relevant equations I'm not sure. 3. The attempt at a solution I'm thinking I need to maybe look at the kinectic energy but I'm sort of mystified. Any help is appreciated.