Question

A body is moving along a circular path of radius R. What will be the distance travelled and displacement of the body when it completes half a revolution?

Answer 1

When the body completes a full revolution then distance will be equal to the circumference of the circular path

So. Distance = .
For the half revolution, it will be .

Displacement is the straight line distance between the initial and final position

So,
Displacement will be 2R which is the length of the diameter.