Question

A body is moved along a closed loop. Is the work done in moving the body necessarily zero? If not, state the condition under which work done over a closed path is always zero.

Answer 1

Work done by a force on a body moving in closed path is zero only when force is conservative.

Work done by non-conservative force are path dependent not only initial and final position.

Therefore, for non-conservative force like friction force, viscous force etc work done in a closed path is not zero.

Final answer: No, work done over each closed path is necessarily zero only if the forces acting on the system are conservative.