$A$ force of $10 \, N$ acts on a body of mass $20 \, kg$ for $10 \, s$. The change in its momentum is ........... $kg \cdot m/s$.

$A$ force of $50\, dynes$ acts on a body of mass $5\, g$ which is at rest for an interval of $3\, seconds$. The impulse is:

$A$ particle moves in the $x-y$ plane under the action of a force $\vec F$ such that the value of its linear momentum $\vec P$ at any time $t$ is $P_x = 2 \cos t$ and $P_y = 2 \sin t$. The angle between $\vec F$ and $\vec P$ at a given time $t$ will be:

$A$ batsman hits back a ball of mass $0.4 \; kg$ straight in the direction of the bowler without changing its initial speed of $15 \; ms^{-1}$. The impulse imparted to the ball is $\dots \; Ns$.

When a bullet is fired from a rifle, its momentum becomes $20 \,kg \cdot m/s$. If the velocity of the bullet is $1000 \,m/s$, then what is its mass?

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