1. The problem statement, all variables and given/known data A ball bounces down a uniform flight of stairs of height H , rising after each bounce to to the level h of the previous stair . the velocity of the ball before the impact is equal in all the impacts . what is the average power of energy loss ? 2. Relevant equations 3. The attempt at a solution first attempt : at points A ,B, the ball has just a potential energy, ball’s horizontal velocity seems to be not relevant (cancel out ). in A - E = mg(h+H) in B - E = mgh EA = EB + Wothers Wothers = mg(h+H) - mgh = mgh .... So the energy loss is actually a constant .... what i'm missing ?