A lever is a simple machine consisting of a movable bar that pivots on a fulcrum, enabling the application of force to achieve movement or lift objects. There are three primary classes of levers, distinguished by the relative positions of the fulcrum, load, and applied force.
The lever is a movable bar that pivots on a fulcrum attached to a fixed point. The lever works by applying
forces at different distances from the fulcrum, or a pivot. For your arm, leg or any part of the body to move
muscles and bones must work together like a series of levers.
Production of rotation on the levers
For rotation to occur, an eccentric force must be applied. Class 1 lever built for balance, Class 2 lever to save effort, and Class 3 lever for speed and range of motion.