The qualitative definition of force is given by

$A$ girl of mass $50 \, kg$ jumps out of a moving boat of mass $300 \, kg$ onto the bank with a horizontal velocity of $3 \, m s^{-1}$. With what velocity will the boat begin to move backwards (in $, m s^{-1}$)?

Two balls $A$ and $B$ of masses $m$ and $2m$ are in motion with velocities $2V$ and $V$ respectively. Compare:
$(i)$ their inertia,
$(ii)$ their momentum,and
$(iii)$ the force needed to stop them in the same time.

State the law of conservation of momentum. Mention two factors which determine the momentum of a body. $A$ ball of mass $0.4 \ kg$ is thrown vertically upwards with a velocity of $10 \ m s^{-1}$. What will be its initial momentum and what would be its momentum at the highest point of its reach? If this change in momentum occurs in one second, find the negatively accelerating force acting on the ball, when it was going up.

While dusting a carpet,we suddenly jerk or beat it with a stick because:

$A$ passenger in a moving car slips to one side of the seat when the car takes a sharp turn. Give the reason for this.