I know that a force will cause a torque if the force has a perpendicular component to the distance from the pivot point. However, in the figure above, I can't seem to visualize how the weight of this bob would create a torque about the pendulum's suspension point?

**EDIT: I know how to calculate the torque mathematically but I can't seem to understand the mechanism through which the toque is applied on the suspension point… does the string have a role in it?**

## Best Answer

The weight vector, $W=mg$, can be split up into two components, $mg\sin\theta$ and $mg\cos\theta$, where $\theta = 30$ in your case. The $mg\sin\theta$ is the force vector which would generate a torque, $\tau = \bf{L}\times{}mg\sin\theta$.