Question

An athlete complete one round of a circular track of radius 7m in 10 sec . Find his average speed and average velocity.

Answer 1

Velocity = displacement/ time.
Here, Displacement= 0 m (as the athlete goes round a circular track)
time = 10 s
Hence, velocity = 0 m/10s
                             = 0 m/s.        

Answer 2

speed = distance / time 
distance = circumference of circle = 2πr = 2 * 22/7 * 7 = 44m
           = 44/10 m/s
velocity = displacement / time
As the athlete moves in a circular path displacement is zero
             = 0/10 = 0 m/s