Question

A simple pendulum of length l is pulled aside to make an angle θ with the vertical. Find the magnitude of the torque of the weight w of the bob about the point of suspension. When is torque zero ?

Answer 1

Given in the question :-

Simple pendulum is suspended there by a rigid support.

Weight = W (Hanging)

Now,

At the angle $\theta$ , the total torque is working on the point of suspension.

i = F × r

The weight of the bob is W

Now, The torque of the weight at the point of suspension .

$= r * w$

 $= wl. sin\theta$

Here the torque direction is perpendicular to the plane.

Hence When the body passes by suspension points, then at the lowest point of suspension the given torque will leads to be Zero.

Hope it Helps . :-)