An athlete starts from a fixed point on a circular track of radius 40m, runs one complete lap and returns to the starting point.
(i) Calculate the distance covered and the displacement of the athlete after completing the lap.
(ii) Using your results from part (i), explain why the average speed of the athlete during the lap is not zero whereas the average velocity is zero.
(iii) On the basis of your explanation, state which of the two quantities, speed and velocity, is a scalar and which is a vector, giving a brief reason.