http://img395.imageshack.us/img395/6158/steelballxu7.gif [Broken] A 35 g steel ball bounces elastically on a steel plate, always returning to the same maximum height h = 20.8 m. a) With what speed does the ball leave the plate? b) What is the magnitude of the total change in momentum of the ball with each bounce? c) What is the magnitude of the total momentum the ball transfers to the plate at each bounce? d) What is the time interval between bounces? e) Averaged over a long time interval, what is the magnitude of the rate at which momentum is transferred to the plate? f) What is the magnitude of the average force exerted by the ball on the plate? g) What is the weight of the ball? Conservation of energy and momentum i believe will have to be used here. I figured out part a.) I set the Kinetic energy equal to the work done by gravity and found the ball moves at 20.199 m/s. It's part b.) that i'm having the problem with. I initially thought the magnitude would have to be zero since the ball would have to moving at the same speeds to continue reaching the same height. But now i feel that it will have to be moving faster coming back up because it will counteract gravity whereas when its moving down it's moving with gravity. I just can't figure out a way to put that into an equation.