Question:
A simple pendulum of length $I$ is pulled aside to make an angle $\theta$ with the vertical. Find the magnitude of the torque of the weight $w$ of the bob about the point of suspension. When is the torque zero?
Solution:
rorque $=F \times d_{\perp}$
$\tau=\omega l \sin \theta$
Torque will be zero at the lowest point of suspension as $\theta$ will be zero.