question_answer

A body of mass m is moving in a circle of radius r with a constant speed v. The force on the body is\[\frac{m{{\upsilon }^{2}}}{r}\] and is directed towards the centre. What is the work done by this force in moving the body over half the circumference of the circle?

Answer:

                Work done by the force is zero, because the direction of displacement of the body at every point is perpendicular to the direction of force acting on the body.