$A$ ping-pong ball of mass $m$ is floating in air by a jet of water emerging out of a nozzle. If the water strikes the ping-pong ball with a speed $v$ and just after collision the water falls dead,the rate of flow (in $kg/s$) of water in the nozzle is equal to

$A$ stream of glass beads, each with a mass of $15 \ g$, comes out of a horizontal tube at a rate of $100 \ \text{beads per second}$. The beads fall a distance of $5 \ m$ to a balance pan and bounce back to their original height. How much mass (in $kg$) must be placed in the other pan of the balance to keep the pointer at zero?

$A$ body of mass $2 \,kg$ collides with a wall with a speed of $100 \,ms^{-1}$ and rebounds with the same speed. If the time of contact is $1/50 \,s$,the force exerted on the wall is

$A$ woman throws an object of mass $500\,g$ with a speed of $25\,ms^{-1}$.
$(a)$ What is the impulse imparted to the object?
$(b)$ If the object hits a wall and rebounds with half the original speed,what is the change in momentum of the object?

$A$ body of mass $m_1$ exerts a force on another body of mass $m_2$. If the magnitude of acceleration of $m_2$ is $a_2$,then the magnitude of the acceleration of $m_1$ is (considering only two bodies in space).

When a $4 \,kg$ rifle is fired,the $10 \,g$ bullet receives an acceleration of $3 \times 10^6 \,cm/s^2$. The magnitude of the force acting on the rifle (in newton) is ............