An artillery piece of mass $M_1$ fires a shell of mass $\mathrm{M}_2$ horizontally. Instantaneously after the firing, the ratio of kinetic energy of the artillery and that of the shell is:

A gun fires a bullet of mass $50 \,gm$ with a velocity of $30\,m\,{\sec ^{ - 1}}$. Because of this the gun is pushed back with a velocity of $1\,m\,{\sec ^{ - 1}}$. The mass of the gun is .......... $kg$

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

Two billiard balls of mass $0.05\,kg$ each moving in opposite directions with $10\,ms ^{-1}$ collide and rebound with the same speed. If the time duration of contact is $t=0.005\,s$, then $\dots N$is the force exerted on the ball due to each other.

A body at rest explodes into two pieces of unequal mass. The parts will move

A cannon ball is fired with a velocity $200\, m/sec$ at an angle of $60^o$ with the horizontal. At the highest point of its flight it explodes into $3$ equal fragments, one going vertically upwards with a velocity $100\, m/sec$, the second one falling vertically downwards with a velocity $100\, m/sec$. The third fragment will be moving with a velocity