explain why a centripetal force does not work on a circularly moving object?

Question

explain why a centripetal force does not work on a circularly moving object?

Answer 1

Work is commonly defined as the dot product of force and displacement. Essentially this means that you are moving in the same or exact opposite direction as your field lines for your given force. Example: Friction does work to stop a moving box as the force is directed anti-paralell to your direction of travel.

When you move in a circle, centripetal force is always directed toward the inside of the circle, which is exactly perpendicular to your direction of motion in the circle. Since the force is perpendicular to the direction of motion, there is no work done.

Answer 2

I would like to add to Mathew's correct answer. Any force produces an acceleration in a body in its own direction. if you apply force on a moving body so that it is always perpendicular to the velocity of the body, then such a force can only change the direction of its motion in a continuous manner but cannot change its speed, because a force cannot produce any effect in a direction perpendicular to it's own direction. So energy of the body does not increase. so no energy transfer takes place and hence no work is done.