$A$ body is dropped on the ground from a height $h_1$ and after hitting the ground,it rebounds to a height $h_2$. If the ratio of velocities of the body just before and after hitting the ground is $4$,then the percentage loss in kinetic energy of the body is $\frac{x}{4}$. The value of $x$ is $.......$

$A$ body falling from a height of $10\,m$ rebounds from a hard floor. If it loses $20\%$ of its energy in the impact,then the coefficient of restitution is:

$A$ ball moving with a velocity $v$ collides head-on with a stationary second ball of the same mass. After the collision,the velocity of the first ball is reduced to $0.15 v$. The kinetic energy of the system is decreased nearly by (in $\%$)

$A$ spherical ball $A$ of mass $4 \ kg$,moving along a straight line,strikes another spherical ball $B$ of mass $1 \ kg$ at rest. After the collision,$A$ and $B$ move with velocities $v_1 \ ms^{-1}$ and $v_2 \ ms^{-1}$ respectively,making angles of $30^{\circ}$ and $60^{\circ}$ with respect to the original direction of motion of $A$. The ratio $\frac{v_1}{v_2}$ will be

$A$ ball is dropped from a height $h$. After it strikes the ground twice,what height will it reach?

$A$ ball of mass $m$ moving with a velocity of $9 \ m/s$ collides with another ball of the same mass $m$ at rest. After the collision,both balls move at an angle of $30^\circ$ with the original direction of motion. Find the velocity $v$ of both balls after the collision. (in $m/s$)