The motion of a rocket is based on the principle of conservation of

A cart loaded with sand moving with velocity $v$. Sand is falling through the hole as shown in diagram then after falling on the ground sand is

A ball is moving towards the wall as shown in diagram then its momentum is conserved

A bullet of mass $40 \,g$ is fired from a gun of mass $10 \,kg$. If velocity of bullet is $400 \,m / s$, then the recoil velocity of the gun will be ..........

A bullet of $'4\,g'$ mass is fired from a gun of mass $4 \,{kg}$. If the bullet moves with the muzzle speed of $50\, {ms}^{-1}$, the impulse imparted to the gun and velocity of recoil of gun are :

A body of mass $M$ at rest explodes into three pieces, in the ratio of masses $1: 1: 2$. Two smaller pieces fly off perpendicular to each other with velocities of $30 \,ms ^{-1}$ and $40 \,ms ^{-1}$ respectively. The velocity of the third piece will be ............... $\,ms ^{-1}$