Q. 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) 0
B) $\left( \begin{array}{r}
\frac{mv^{2}}{l} \\
\
\end{array} \right).2\pi l$
C) $mg.2\pi$
D) $\left( \begin{array}{r}
\frac{mv^{2}}{l} \\
\
\end{array} \right).(l)$
Explanation
(a) Work done by centripetal force in uniform circular motion is always equal to zero
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.