A jet engine works on the principle of

A mass $m$ moving horizontally (along the $x-$ axis) with velocity $v$ collides and sticks to a mass of $3m$ moving vertically upward (along the $y-$ axis) with velocity $2v$. The final velocity of the combination is

A man is standing at the centre of frictionless pond of ice. How can he get himself to the shore

An object of mass $2 \,kg$ at rest at origin starts moving under the action of a force $\vec{F}=\left(3 t^2 \hat{i}+4 \hat{j}\right) N$ The velocity of the object at $t=2 \,s$ will be ............. $m / s$

A bomb of mass $9 \,kg$ explodes into two pieces of masses $3 \,kg$ and $6 \,kg$. The velocity of mass $3 \,kg$ is $16 \,m / s$. The kinetic energy of mass $6 \,kg$ in joule is

A rifle man, who together with his rifle has a mass of $100\,kg$, stands on a smooth surface and fires $10$ shots horizontally. Each bullet has a mass $10\,g$ and a muzzle velocity of $800\,ms ^{-1}$. The velocity which the rifle man attains after firing $10$ shots is $..........\,ms^{-1}$