20 Physics -- Work, Energy and Power

A body kept moving with uniform speed in a circle by a centripetal force acting on it. However, the work done by this force is zero. Is it true? Explain.

A body kept moving with uniform speed in a circle by a centripetal force acting on it. However, the work done by this force is zero. Is it true? Explain.

✓✓ Work done is equal to Force (acting in the direction of displacement) times the displacement i.e. W=F.S where (.) is dot product. For the work done we need component of force along the direction of displacement but displacement and force are 90°, at each and every point on the circular track and therefore the component of force along the direction of displacement will always be zero in case of a body moving in a circular track or a body performing circular motion. We know W=F.S or F.Scos, since body is moving in circular track cos=0 , and hence whole term will be 0 i.e. Work done will be 0.

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