$A$ bus decreases its speed from $80 \, km \, h^{-1}$ to $50 \, km \, h^{-1}$ in $4 \, s$. Find the acceleration of the bus.

State which of the following situations are possible and give an example of each of these:
$(a)$ $A$ body moving with constant acceleration but with zero velocity.
$(b)$ $A$ body moving horizontally with an acceleration in the vertical direction.
$(c)$ $A$ body moving with a constant speed in an accelerated motion.

An electric train is moving with a velocity of $120 \, km \, h^{-1}$. How much distance will it cover in $30 \, s$ (in $, km$)?

Explain with reason,which of the following graphs can possibly represent the motion of a particle observed in nature?

What is a velocity-time graph? State how it can be used to find:
$(i)$ The acceleration of a body.
$(ii)$ The displacement of the body.
$(iii)$ The distance travelled in a given time.

Can a particle be accelerated
$(i)$ if its speed is constant?
$(ii)$ if its velocity is constant?