Can a body rotate even if net force acting on it is zero? Can a single force stop a body from rotation, if the body is rotating under the action of a 'couple'? Explain.

Explanation

A couple acting on a body rotates it, if the body is free to rotate. A couple is formed by two equal forces acting in opposite directions, though their lines of action are not same. The net force acting on a body under the action of a couple is zero, though the body rotates. When a body rotates under the action of a couple, it cannot be stopped from rotating by applying a single force. To stop it from rotating, a couple of equal magnitude but in opposite sense of applied couple is required.