A body of mass $0.25 \,kg$ is projected with muzzle velocity $100\,m{s^{ – 1}}$ from a tank of mass $100\, kg$. What is the recoil velocity of the tank …….. $ms^{-1}$

A shell at rest at the origin explodes into three fragments of masses $1\ kg$ , $2\ kg$ and $m\ kg$ . The $1\ kg$ and $2\ kg$ pieces fly off with speeds of $5\ ms^{-1}$ along $x-axis$ and $6\ ms^{-1}$ along $y-axis$ respectively. If the $m\, kg$ piece flies off with a speed of $6.5\ ms^{-1}$ , the total mass of the shell must be    ……… $kg$

A bullet of mass $5 \,g$ is shot from a gun of mass $5 \,kg$. The muzzle velocity of the bullet is $500\, m/s$. The recoil velocity of the gun is ……….. $m/s$

Rocket engines lift a rocket from the earth surface because hot gas with high velocity

If final momentum is equal to initial momentum of the system then