$A$ ball is dropped from a height of $20 \ m$. If it loses $20\%$ of its energy upon collision with the ground,what is the coefficient of restitution?

$A$ ball is dropped from a height $h$. It bounces repeatedly off the ground. What is the total distance covered by the ball before it comes to rest?

$A$ ball is dropped from a height $h$. As it bounces off the floor,its speed is $80$ percent of what it was just before it hit the floor. The ball will then rise to a height of most nearly .............. $h$.

Two balls $A$ and $B$ having masses $1 \ kg$ and $2 \ kg$,moving with speeds $21 \ m/s$ and $4 \ m/s$ respectively in opposite directions,collide head-on. After the collision,$A$ moves with a speed of $1 \ m/s$ in the same direction. The coefficient of restitution is:

$A$ uniform rod of mass $M$ and length $L$ is placed on a smooth horizontal surface. $A$ particle of mass $m$ strikes the rod at one end with a velocity $v$ perpendicular to the rod. If the particle comes to rest after the collision,the velocity of the center of mass of the rod after the collision is:

$A$ body of mass $m$ moving with velocity $v$ collides with another body of mass $nm$ moving in the same direction with velocity $kv$. If the first body comes to rest after the collision,what is the velocity of the second body?