# physics

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a ball striking a horizontal plane with a velocity v rebounds with a velocity 256v/625 after 4th collision. the coefficient of restitution is?

• physics -

(256/625)^1/4 = (16/25)^1/2 = 4/5

They deliberately picked a fraction for which both the numerator and deniminator are perfect fourth roots.

The answer is 4/5. Each bounce gives you 80% of the height of the previous bounce.

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