# Revise Mechanics! (2)

A simple pendulum is suspended from a peg on a vertical wall. The pendulum is pulled away from the wall to a horizontal position(see figure) and released. The ball hits the wall, the coefficient of restitution being $$\dfrac{2}{\sqrt5}$$.

What is the minimum number of collisions after which the amplitude of oscillations becomes less than 60 degrees?

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