Levers can be understood by applying the principle of Torque.
An object that rotates about a fixed point or about an axis because of a force being applied to it has Torque.
When a force is applied to a lever or rotating arm (an object attached to a fixed support by a pivoting point or hinge), the lever will move in a rotational motion.
The (angular) acceleration on the arm increases if
- a) the force increases
- b) the length of the arm increases
The unit of torque is the Newton-meter [Nm].
If a 40 Kg rock needs to be raised using a 3.0 m lever, what will the resulting torque be on the rock?
Given: m = 40 Kg d = 3.0 m g = 9.8 N/Kg
need to find Fg first
Fg = m x g
= 40 Kg x 9.8 N/Kg
= 392 N
t = F x d
= 392 N x 3.0 m
= 1176 Nm