Question

Does tension do work on a pendulum

Answer 1

Explanation

1. The tension in a pendulum is known to be perpendicular to the motion of the bob. Therefore, the tension does not do any work on the bob of the pendulum.
2. Work done $W=F·S\cos \theta$, (where, $F$ is force, $\theta$ is an angle and $S$ is displacement),
3. Hence the work done also depends on the angle $\theta$ inspite of Force $F$ and displacement $S$.
4. Since the tension in a pendulum is known to be perpendicular which means $\theta =90°$, to the motion of the bob.
5. Therefore, $W=F·S\cos \left(90°\right),$ which means the workdone $W=0$. So work done by tension is zero.

Hence, the tension does not do any work on the bob of the pendulum.