$A$ particle of mass $m$ strikes a wall with speed $v$ at an angle $30^{\circ}$ with the wall elastically as shown in the figure. The magnitude of impulse imparted to the ball by the wall is

$A$ 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?

Explain why the product of mass and velocity is important in producing the effect of force.

$A$ boy hits a baseball with a bat and imparts an impulse $J$ to the ball. The boy hits the ball again with the same force,except that the ball and the bat are in contact for twice the amount of time as in the first hit. The new impulse equals:

$A$ machine gun fires a bullet of mass $40\,g$ with a velocity $1200\,m/s$. The man holding it can exert a maximum force of $144\,N$ on the gun. How many bullets can he fire per second at the most?

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 ............