In your everyday life, you come across a range of motions in which

$(a)$ acceleration is in the direction of motion.

$(b)$ acceleration is against the direction of motion.

$(c)$ acceleration is uniform.

$(d)$ acceleration is non$-$uniform.

Can you identify one example each of the above type of motion ?

An object is dropped from rest at a height of $150\, m$ and simultaneously another object is dropped from rest at a height $100 \,m$. What is the difference in their heights after $2\,\sec $ if both the objects drop with same accelerations ? How does the difference in heights vary with time ?

Diagram shows a velocity$-$time graph for a car starting from rest. The graph has three sections $A B$, $B C$ and $C D$

$(i)$ From a study of this graph, state how the distance travelled in any section is determined.

$(ii)$ Compare the distance travelled in section $BC$ with distance travelled in section $A B$.

$(iii)$ In which section car has zero acceleration ?

$(iv)$ Is the magnitude of acceleration higher or lower than, that of retardation ? Give reason.

A motor bike running at $90\, km h ^{-1}$ is slowed down to $18 \,km h^{-1}$ in $2.5\, s$. Calculate

$(i)$ acceleration

$(ii)$ distance covered in the time it slows down

Can the speed of a body be negative ?