A lead ball strikes a wall and falls down, a tennis ball having the same mass and velocity strikes the wall and bounces back. Check the correct statement

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 simple pendulum of length $1 \mathrm{~m}$ has a wooden bob of mass $1 \mathrm{~kg}$. It is struck by a bullet of mass $10^{-2} \mathrm{~kg}$ moving with a speed of $2 \times 10^2 \mathrm{~ms}^{-1}$. The bullet gets embedded into the bob. The height to which the bob rises before swinging back is. (use $\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2$ )

A vessel at rest explodes into three pieces. Two pieces having equal masses fly off perpendicular to one another with the same velocity $30$ meter per second. The third piece has three times mass of each of other piece. The magnitude and direction of the velocity of the third piece will be

An object of mass $3\,m$ splits into three equal fragments. Two fragments have velocities $v\hat j$ and $v\hat i$. The velocity of the third fragment is

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: