A glass ball is shot to hit a wall from a point on a smooth floor. If the ball returns back to the point of projection in twice the time taken in reaching the wall, the coefficient of restitution between the glass ball and the wall is

ANS:D - 0.50

Let suppose: T=wall, 2T=projection pt.

Now, co-efficient of restitution
= h/H = wall/projection pt.
= T/2T,
= 0.50 Ans.