×

# Torque

While calculating torque, we assume that the force to the moment is perpendicular to it. I was wondering, what would happen if its not perpendicular. Please help!

Note by Tanay Roman
4 years, 3 months ago

Sort by:

Use VECTORS. · 4 years, 3 months ago

Torque is r X F. Take the cross-product. · 4 years, 3 months ago

if it is parallel,and u happen to be strong enough as to break the axis of rotation,linear motion takes place · 4 years, 3 months ago

If the force is not perpendicular, there are two ways of calculating the torque. I refer to this picture.

1. Splitting the force ($$F$$) into two components, one perpendicular to the axis ($$F_h$$) and one directly towards the axis ($$F_v$$). Then the torque $$\tau$$ becomes $$\tau=F_h l=Fl\sin(\theta)$$.

2. Projecting the arm so it's perpendicular to the force. Here, the torque becomes $$\tau=Fl'=Fl\sin(\theta)$$. As you see, the two methods agree, and are actually the same thing.

In more advanced physics, you usually calculate torque using vectors instead: $$\vec \tau=\vec l\times \vec F$$, where $$\|\vec \tau\|=\|\vec l\| \| \vec F\| \sin(\theta)$$. · 4 years, 3 months ago