Question

A sphere of mass m is tied to end of a string of length $ l $ and rotated through the other end along a horizontal circular path with speed v. The work done in full horizontal circle is

• A. zero
• B. $ \left( \frac{m{{v}^{2}}}{l} \right)2\pi l $
• C. $ mg.\,2\pi l $
• D. $ \left( \frac{m{{v}^{2}}}{l} \right)(l) $

Answer 1

Answer: (A)

Work done by centripetal force in uniform circular motion is always equal to zero.