# Energy conversion efficiency of each bounce

postie
1. i drop a ball (mass 20 grammes) from a height of 10 meters, after 3 bounces it rises to a height of 2 meters, what is the energy conversion efficiency of each bounce?

2. I've been stuck on this for the last hour and have nothing any help would be great.

3.the closest i got was doing 10× random percentages 3 times and seeing how close i got

## Answers and Replies

Gold Member
Welcome to PF!

Can you define, as an equation, what "energy conversion efficiency" means for a single bounce? (hint: it involves the kinetic energy of the ball before and after a bounce, and a conversion factor). Can you relate the kinetic energy of the ball when it is at zero height just before a bounce with the potential energy when it earlier was at height h, but with zero speed? Can you utilize all this to relate the drop height from before the first bounce to the bounce height after the last bounce? What must you assume about the conversion factor in order to do this?