Explain that a can have zero average velcoity but not zero average speed.

Explanation

Average velocity=displacement //(total time taken) and average speed =total distance travelled//(total taken ) .If an object completes a circular path of radius (r ) in time (t), then its displacement is zero but distanc etravelled by body is ` 2 pi r`. Therefore, the average velocity of body =zero but average speed of body ` =2 pir//t`.