$A$ body of mass $M$ moves with velocity $v$ and collides elastically with another body of mass $m$ $(M >> m)$ at rest. Then,the velocity of the body of mass $m$ is:

Body $A$ of mass $4m$ moving with speed $u$ collides with another body $B$ of mass $2m$ at rest. The collision is head-on and elastic in nature. After the collision, the fraction of energy lost by the colliding body $A$ is:

$A$ sphere of mass $0.1 \ kg$ is attached to a string of length $1 \ m$. It is released from a horizontal position and collides with another sphere of equal mass $m$ at rest. Find the kinetic energy gained by the second sphere. The collision is perfectly elastic. (in $J$)

$A$ ball of mass $m$ moving with speed $u$ undergoes a head-on elastic collision with a stationary ball of mass $nm$. What is the fraction of the kinetic energy transferred to the heavier ball?

$A$ sphere of mass $M$ moving with velocity $u$ undergoes a perfectly elastic collision with a stationary sphere of mass $m$. If their velocities after the collision are $V$ and $v$ respectively,what is the value of $v$?

$A$ 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