If the average velocity of a body is equal to the mean of its initial velocity and final velocity,then the acceleration of the body is

Give an expression for the speed of an athlete if he takes time $t$ to complete one round of a circular track of radius $r$.

Give one example for each of the type of motion when
$(i)$ acceleration is in the direction of motion.
$(ii)$ acceleration is against the direction of motion.
$(iii)$ acceleration is uniform.

Write any two equations of motion for a body having uniform acceleration.

Which of the following is not a vector?

In a long distance race,the athletes were expected to take four rounds of the track such that the finish line was the same as the start line. Suppose the length of the track was $200 \ m$.
$(a)$ What is the total distance to be covered by the athletes?
$(b)$ What is the displacement of the athletes when they touch the finish line?
$(c)$ Is the motion of the athletes uniform or nonuniform?
$(d)$ Is the displacement of an athlete and the distance moved by him at the end of the race equal?