If the final momentum is equal to the initial momentum of the system,then:

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?

$A$ ball of mass $3 \ kg$ strikes a wall at an angle of $60^\circ$ with a velocity of $10 \ m/s$ and rebounds at the same angle and speed. What is the change in momentum of the ball in $MKS$ units?

$A$ $2 \ kg$ object is initially at rest. It is acted upon by a force as indicated in the figure. Find the total work done by the force in $3 \ s$. (in $J$)

In projectile motion,two particles of masses $m_1$ and $m_2$ have velocities $\vec{V}_1$ and $\vec{V}_2$ respectively at time $t=0$. Their velocities become $\vec{V}_1^{\prime}$ and $\vec{V}_2^{\prime}$ at time $2t$ while still moving in air. The value of $[(m_1 \vec{V}_1^{\prime} + m_2 \vec{V}_2^{\prime}) - (m_1 \vec{V}_1 + m_2 \vec{V}_2)]$ is ($g =$ acceleration due to gravity).

The figure shows the position-time $(x-t)$ graph of one-dimensional motion of a body of mass $0.4 \; kg$. The magnitude of each impulse is: