Study the speed-time graph of a car given below and answer the questions that follow

$(i)$ What type of motion is represented by $OA$ ?

$(ii)$ What type of motion is represented by $A B$ ?

$(iii)$ What type of motion is represented by $BC$ ?

$(iv)$ What is the acceleration of the car from $O$ to $A$ ?

$(v)$ What is the acceleration of the car from $A$ to $B$ ?

$(vi)$ What is the retardation of car from $B$ to $C$ ?

"The direction in which an object moves is given by the direction of velocity of the object and not by the direction of acceleration". Give an example to justify this statement

Two stones are thrown vertically upwards simultaneously with their initial velocities $u _{1}$ and $u _{2}$ respectively. Prove that the heights reached by them would be in the ratio of $u_{1}^{2}: u_{2}^{2}$ (Assume upward acceleration is $-\,g$ and downward acceleration to be $+g$.

What can you say about the motion of an object whose distance time graph is

$(i)$ a straight line, parallel to the time axis ?

$(ii)$ a straight line passing through the origin making an angle with the time axis ?

State the meaning of uniform circular motion.