A simple pendulum is hanging from a per inserted in a vertical wall. Its bob is stretched to horizontal position from wall and is left free to move, the bob hits the wall. If coefficient of restitution is (2)/(sqrt(5)). After how many collisions the amplitude of vibration will become less than 60^(@)

A simple pendulum is hanging from a per inserted in a vertical wall. I

1.	A simple pendulum is hanging from a per inserted in a vertical wall. Its bob is stretched to horizontal position from wall and is left free to move, the bob hits the wall. If coefficient of restitution is (2)/(sqrt(5)). After how many collisions the amplitude of vibration will become less than 60^(@)
Answer» `6` `3` `5` `4` ANSWER :B