$A$ ball is dropped from a height of $20\,m$. If the coefficient of restitution for the collision between ball and floor is $0.5$,after hitting the floor,the ball rebounds to a height of $.............m$.

$A$ $2 \,kg$ ball moving at $24 \,ms^{-1}$ undergoes inelastic head-on collision with a $4 \,kg$ ball moving in the opposite direction at $48 \,ms^{-1}$. If the coefficient of restitution is $2/3$, their velocities in $ms^{-1}$ after impact are

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 is dropped from a height of $5 \ m$ on a planet. It rebounds to a height of $1.8 \ m$. What is the fraction of velocity lost by the ball?

$A$ ball kept at $20 \,m$ height falls freely in a vertically downward direction and hits the ground. The coefficient of restitution is $0.4$. What is the velocity of the ball after the first rebound (in $\,ms^{-1}$)? $\left[g=10 \,ms^{-2}\right]$

$A$ body falls from a height of $10 \ m$ onto the ground and rebounds to a height of $2.5 \ m$. The percentage loss in kinetic energy is ......... $\%$.