A simple pendulum of length l is pulled aside to make an angle θ with the vertical. Find the magnitude torque of the weight w of the bob about the point of suspension. When is the torque zero?
, at lowest point the 
, turning the torque equal to zero at the lowest point.
Given
The length of the pendulum is given as l, and the angle after pull is given as
. The weight of the bob is weight “w”.
Formula Used
The formula used is that of a torque which tells us the mechanics of force which helps the object to rotate. The formula is
where
F is the force applied on the object; r is the radius of the object turning.
Explanation
The pendulum bob rotates at a distance of “l” from the center which is also the radius in terms of torque, the force is taken as
The angle of turning is taken as
; therefore, radius in terms of turning angle is
Therefore, the torque of the pendulum is
Hence, at lowest point the 
, turning the torque equal to zero at the lowest point.