$N$ number of balls,each of mass $m \ kg$,moving along the positive direction of the $x$-axis,strike a wall per second and return elastically. The velocity of each ball is $u \ m/s$. The force exerted on the wall by the balls in newtons is:

$A$ particle moves in the $x-y$ plane under the influence of a force $\vec{F}$ such that its linear momentum is $\vec{P}(t) = \hat{i} \cos(kt) - \hat{j} \sin(kt)$. If $k$ is a constant,the angle between $\vec{F}$ and $\vec{P}$ will be:

$A$ metal ball hits a wall and does not rebound,whereas a rubber ball of the same mass hits the wall with the same velocity and rebounds. What can be concluded from this?

$A$ body of mass $3\,kg$ is acted on by a force which varies as shown in the graph below. The momentum acquired is given by ........... $N-s$.

$A$ ball of mass $0.15 \; kg$ hits the wall with an initial speed of $12 \; m/s$ and bounces back without changing its initial speed. If the force applied by the wall on the ball during the contact is $100 \; N$,calculate the time duration of the contact of the ball with the wall in seconds.

$A$ ball is thrown up at an angle with the horizontal. Then,the total change of momentum by the instant it returns to the ground is