Usha swims in a 90 m long pool. She covers 180 m in one minute by swimming from one end to the other and back along the same straight path. Find the average speed and average velocity of Usha.

Solution:
Total distance covered by Usha in 1 min is 180 m.
Displacement of Usha in 1 min = 0 m
Average speed = Total distance covered / Total time taken

= 180 m / 1 min = 180 m / 60 s = 3 m s^-1
Average velocity = Displacement / Total time taken = 0 m / 60 s = 0 m s^–1
The average speed of Usha is 3 m s^–1
and her average velocity is 0 m s^–1
.