Give an expression for the speed of an athlete if he takes time $'t^{\prime}$ to go around a circular track, of radius ${ }^{\prime} r^{\prime}$
A boy hits a football high up into the air. He runs and catches the football before it hits the ground. Which of the two, the boy or the football has had greater displacement ?
If the average velocity of a body is equal to mean of its initial yelocity and final velocity, then the acceleration of the body is
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.
Two cars $A$ and $B$ have their displacement$-$time graph as given below. Which car has a greater velocity ?