A highly elastic ball moving at a speed of `3 m//s` approaches a wall moving towards it with a speed of `3 m//s`. After the collision. the speed of the ball will be

Options

A. 3 m/s
B. 6 m/s
C. 9 m/s
D. zero

Answer

C

Explanation

For elastic colliso, e = 1. Let speed of the ball be v towards left after collision, then w.r.t. wall, incident velocity = reflected velocity. We get, `3 + 3 = v - 3 implies v = 9 m//s`.