Question

A sphere of mass $m$ is tied to end of 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. $0$
• B. $\left(\frac{m{v}^2}{l}\right)2\pi l$
• C. $mg2\pi l$
• D. $\left(\frac{m{v}^2}{l}\right)l$

Answer 1

The correct option is A $0$

As centripetal force is always perpendicular to the direction of motion at any instant and hence work done =0