$A$ 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 ......... $km/h$.

$A$ stationary particle explodes into two particles of masses $x$ and $y$,which move in opposite directions with velocities $v_1$ and $v_2$. The ratio of their kinetic energies $(E_1: E_2)$ is

$A$ shell of mass $m$ moving with velocity $v$ suddenly breaks into two pieces. If one of those parts having mass $m/6$ remains stationary,find the velocity of the other part.

$A$ jet engine works on the principle of

$A$ body of mass $5 \ kg$ initially at rest explodes into three fragments. The ratio of the masses of the three fragments is $1 : 1 : 3$. The two fragments of equal mass move in mutually perpendicular directions with a velocity of $21 \ m/s$. What is the velocity of the heaviest fragment in $m/s$?

$A$ bomb of $12 \ kg$ divides into two parts whose ratio of masses is $1 : 3$. If the kinetic energy of the smaller part is $216 \ J$,then the momentum of the bigger part in $kg \cdot m/s$ will be: