Question

A body can have 0 average velocity but not 0average speed.justify giving an example

Answer 1

circulatory motion of a body, when a body start to rotate nd then comes to its initial position, at that instant tha velocity of the body is zero as the displacement becomes zero. But the distance covered by the body at that instant will be
$2\pi \: r$
which result the speed of body is not zero.

Answer 2

Average velocity is defined as the ratio of total displacement by TOTAL time taken.
Average speed is the ratio of total distance by TOTAL time taken.
As average velocity depends on displacement and displacement can be zero if the object returns to initial position .
Where as distance can never be zero for a journey.

Example:
A person completes one revolution in circular path.
Distance = 2 *pi*r
Whereas displacement is zero as source and destination is same.

Hence A body can have zero average velocity but not zero average speed.

Hope it's helpful to uh..

Thank-you.