When a body moves with a constant speed along a circle, it undergoes uniform circular motion. In this motion, the centripetal force acting on the body is directed radially inwards towards the centre of the circle, while the instantaneous displacement is tangential to the circular path . Since the angle between the force and the displacement vectors is always $90^\circ$ (mutually perpendicular), the work done by the centripetal force is zero ($W = Fd \cos 90^\circ = 0$) .

Additionally, the velocity is not constant because its direction changes continuously along the circular path , which means an acceleration is produced and a net force acts on the body.