If the coefficient of restitution is $0.5$,what is the percentage loss of energy on each rebounding of a ball dropped from a height?

$A$ 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 $.......$

$A$ sphere of mass $m$ moving with velocity $u$ undergoes a collision with a stationary sphere of mass $m$. If the coefficient of restitution is $e = 1/2$,what is the ratio of the final velocities of the two spheres?

Two solid rubber balls $A$ and $B$ having masses $200 \, g$ and $400 \, g$ respectively are moving in opposite directions. The velocity of $A$ is $0.3 \, m/s$. After the collision,both balls come to rest. Determine the velocity of $B$ in $m/s$.

$A$ small ball falling vertically downward with a constant velocity of $4 \ m/s$ strikes elastically a massive inclined cart moving with a velocity of $4 \ m/s$ horizontally,as shown in the figure. The velocity of the rebound of the ball is

$A$ body dropped from a height $1\,m$ on a floor rises to a height $25\,cm$ after the first rebound. The coefficient of restitution is