$A$ ball of mass $m$ moving with a speed $u$ undergoes a head-on elastic collision with a ball of mass $nm$ initially at rest. The fraction of the incident energy transferred to the heavier ball is

$A$ particle of mass $m$ moving with a speed $v$ hits elastically another stationary particle of mass $2m$ in a fixed smooth horizontal circular tube of radius $R$. Find the time when the next collision will take place?

Two balls $A$ and $B$,of masses $M$ and $2M$ respectively,collide with each other. If ball $A$ moves with a speed of $150 \ m \ s^{-1}$ and collides with ball $B$ moving with speed $v$ in the opposite direction,and after the collision ball $A$ comes to rest with the coefficient of restitution being $1$,then the speed of ball $B$ before it collides with ball $A$ is: (in $m \ s^{-1}$)

Five identical elastic balls are suspended in a row with strings of equal length such that the distance between the sides of the balls is very small. If the ball at the right end is released from one side,then:

Two masses $m_1$ and $m_2$ moving with velocities $v_1$ and $v_2$ in opposite directions collide elastically and after collision masses $m_1$ and $m_2$ move with velocity $v_2$ and $v_1$ respectively. The ratio $\left(\frac{m_2}{m_1}\right)$ is

$A$ body of mass $m$ moving with velocity $v$ collides with a stationary body of mass $2m$. The fraction of kinetic energy lost by the body of mass $m$ is: