What type of motion is represented by the following graphs ?

The velocity$-$time graph of an ascending passenger lift is as in the figure shown below

$(i)$ Identify the kind of motion of lift represented by lines $OA$ and $BC$.

$(ii)$ Calculate the acceleration of the lift

$(a)$ During the first two seconds.

$(b)$ Between the $3^ {r d}$ and $10^ {t h}$ second.

$(c)$ During the last two seconds.

What is the relation between distance and time

$(i)$ when body is moving with uniform velocity ?

$(ii)$ when body is moving with variable velocity ?

Two cars moving in opposite directions cover same distance $'d'$ in one hour. If the cars were moving in north$-$south direction, what will be their displacement in one hour ?

$(a)$ A car moving with uniform velocity $'u^{\prime}$ and uniform acceleration $'a^{\prime}$ covers a distance $'S^{\prime}$ in time $'t^{\prime}$. Draw its velocity $-$ time graph and derive an expression relating all the given physical quantities.

$(b)$ A boy revolves a stone tied to a string $0.7 \,m$ long. Find the distance and displacement covered by the stone in completing two revolutions from starting point.