Write answers to the following:
$(i)$ Mention the direction in which the force of friction acts on a moving body. State its units.
$(ii)$ Name the property of bodies (or objects) to resist a change in their state of rest or of motion. Name the quantity that is a measure of this property.
$(iii)$ Name the physical quantity whose unit is $kg\, m s^{-1}$. Define this quantity.

(N/A) $(i)$ The force of friction acts in the direction opposite to the direction of motion of the body. Its $SI$ unit is the newton $(N)$.
$(ii)$ The property of bodies to resist a change in their state of rest or motion is called inertia. Mass is the quantitative measure of inertia.
$(iii)$ The physical quantity is momentum. Momentum is defined as the product of the mass and velocity of a body $(p = mv)$.