"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

$(a)$ Define circular motion.

$(b)$ "Uniform circular motion is an accelerated motion". Justify this statement with reason.

$(c)$ An artificial satellite is moving in a circular orbit of radius $42250\, km.$ Calculate its speed if it takes $24$ hours to revolve once around the earth.

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 $C$ ?

$(a)$ When will you say a body is in

$(i)$ uniform motion $(ii)$ non$-$uniform motion ?

$(b)$ Show the path of an object when it is in uniform motion with the help of a graph.

Give an expression for the speed of an athlete if he takes time $'t^{\prime}$ to go around a circular track, of radius ${ }^{\prime} r^{\prime}$

From the given $v -t$ graph (Fig.), it can be inferred that the object is