$A$ 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 $, N$)?

The quantitative definition of force is given by

Newton's second law of motion gives us a measure of

$(a)$ Define force and state three possible effects of force on an object.
$(b)$ $A$ motorcycle is moving with a velocity of $90 \, km \, h^{-1}$ and it takes $5 \, s$ to stop after the brakes are applied. Calculate the force exerted by the brakes on the motorcycle if its mass along with the rider is $200 \, kg$.

$A$ hockey ball of mass $200 \,g$ travelling at $10 \,m \,s^{-1}$ is struck by a hockey stick so as to return it along its original path with a velocity of $5 \,m \,s^{-1}$. Calculate the magnitude of the change in momentum of the hockey ball due to the force applied by the hockey stick.

It is required to increase the velocity of a scooter of mass $80 \ kg$ from $5 \ m s^{-1}$ to $25 \ m s^{-1}$ in $2 \ s$. Calculate the force required.