$A$ wagon weighing $1000\, kg$ is moving with a velocity of $50\, km/h$ on smooth horizontal rails. $A$ mass of $250\, kg$ is dropped into it. The velocity with which it moves now is ......... $km/h$.

$A$ shell of mass $5 M$, acted upon by no external force and initially at rest, bursts into three fragments of masses $M, 2 M$, and $2 M$ respectively. The first two fragments move in opposite directions with velocities of magnitudes $2 v$ and $v$ respectively. The third fragment will

$A$ bullet of mass $10\, g$ is fired from a gun of mass $1\, kg$. If the recoil velocity of the gun is $5\, m/s$,the muzzle velocity of the bullet is ........ $m/s$.

$A$ bomb at rest explodes into three fragments $X, Y$ and $Z$. Each one of them has the same mass. Which of the following correctly describes the motion of the fragments?

$A$ body of mass $M$ moving with velocity $V$ explodes into two equal parts. If one part comes to rest and the other part moves with velocity $v_{0}$,what would be the value of $v_{0}$?

$A$ spacecraft of mass $M$ moving with velocity $v$ suddenly breaks into two pieces of equal mass $m$. After the explosion,one of the masses $m$ becomes stationary. What is the velocity of the other part of the craft?