Question

a body can have zero average velocity but not zero average speed. Justify giving an example.

Answer 1

as you know the formula that average velocity is equal to displacement/time taken and average speed is equal to distance/time then by analysis these formula you know that distance is never be zero( if a particle moves) whether dispacment will be zero example in circular motion

Answer 2

The velocity of a body refers to the displacement if the body in unit time. The displacement of a body is a vector quantity and it means the shortest distance between its initial and final position. So if a body travels a path and comes back to its initial position, it's displacement is 0. Since v =d(displacement) /t(time), the velocity shall also be 0.

The speed of the body is the distance travelled by the body in unit time . The distance travelled by a body is a scalar quantity and it is the actual length of of path travelled by the body starting from its initial position, to reach its final position ; so even if the body comes back to its starting point, the distance covered will not be 0. Speed =distance /time. So it's speed will not be 0 (units) either

Therefore, a body in motion can have 0 average velocity but can never have 0 average speed.