MediumPhysicsHigh School (11–12)Mechanics › Momentum and CollisionsMechanics › Work, Energy and PowerNumerical
A ball dropped from 1.6 m bounces back to 0.90 m.
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A ball dropped from bounces back to .
- What is the coefficient of restitution?
- How high does it rise after the second bounce?
Need a reminder? The key ideaShow
The coefficient of restitution is . A ball bouncing on a floor keeps the fraction of its speed and of its height each bounce, so .
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Plan. Speeds go as , so comes from the ratio of heights.
Step 1. (a) .
Step 2. (b) .
Answer: (a) . (b) About .
Check. The heights go , , : each is times the last.
Watch out. The ratio of the heights, , is , not .
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