$A$ ball is dropped from some height and after the first collision with the ground,if it reaches $\frac{3}{4}$ of its original height,then the percentage loss of its energy is:

$A$ body falls freely onto a hard horizontal surface. If the coefficient of restitution between the surface and the body is $e = 0.8$,then the ratio of the maximum height to which the body rises after the second impact to the initial height of the body is:

Hail stones are observed to strike the surface of a frozen lake at $30^{\circ}$ with the vertical and rebound at $60^{\circ}$ with the vertical. Assuming the contact to be smooth,the coefficient of restitution is

$A$ ball of mass $M$ falls from a height $h$ on a floor. If the coefficient of restitution is $e$,the height attained by the ball after two rebounds is

$A$ moving block having mass $m$ collides with another stationary block having mass $4m$. The lighter block comes to rest after the collision. If the initial velocity of the lighter block is $v$,then the value of the coefficient of restitution $(e)$ will be:

$A$ ball moving with a velocity of $6\, m/s$ strikes an identical stationary ball. After collision,each ball moves at an angle of $30^{\circ}$ with the original line of motion. What are the speeds of the balls after the collision?