When balanced forces act on a body,the body is

$A$ bullet of mass $10\, g$ is fired from a rifle. The bullet takes $0.003\, s$ to move through its barrel and leaves with a velocity of $300\, m s^{-1}$. What is the force exerted on the bullet by the rifle (in $, N$)?

Two identical bullets are fired,one by a light rifle and another by a heavy rifle with the same force. Which rifle will hurt the shoulder more and why?

$(a)$ State the law of conservation of momentum.
$(b)$ Mention two factors which determine the momentum of a body.
$(c)$ Prove the law of conservation of momentum with clear explanation,diagram and equation.

Which would require a greater force $-$ accelerating a $1\, kg$ mass at $10\, m s^{-2}$ or a $2\, kg$ mass at $4\, m s^{-2}$?

$(i)$ Name the property by virtue of which a body resists a change in its state of motion. Name the physical quantity which is a measure of this property.
$(ii)$ Explain why some of the leaves may get detached from a tree if we vigorously shake its branch.