# Coefficient of restitution

The coefficient of restitution (COR) of two colliding objects is a positive real number between $$0.0$$ and $$1.0$$ representing the ratio of speeds after and before an impact, taken along the line of the impact. When a basketball which has the restitution coefficient of $$e$$ with the floor falls free from the height of $$h,$$ the bounce height is $$h'$$ as above left(A). The above right(B) shows the bounce height $$h'$$ as a function of the drop height $$h.$$ What is $$e?$$

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