Everytime an object completes a circle in uniform circular motion, the displacement of the object is zero as it returns to its starting position.And according to formula of work,
Another reason is that the angular velocity(
I agree with the above, but think it can be explained more simply.
Imagine you are on a satellite orbiting the Earth, your velocity is a tangent to the orbit, the force causing you to remain in orbit (gravity) is at right angles to the velocity vector. Thus no work is done in the direction of the motion, as your displacement from the Earth is constant.
Work is better defined as
#W = F.s cos(theta)#
which reduces to zero when the angle between force and displacement is
If work was done in the direction of travel, your velocity would increase and you would move into a higher orbit.