Lever

From French lever, “to raise”

A rigid object used with an appropriate fulcrum to realize a mechanical advantage.

Archemides said:
“Give me a place to stand, and I shall move the Earth with a lever.”

The ratio of the force applied to each end points of the lever is proportional to the ratio of the length of the lever arm measured between the fulcrum and the force’s application point at each end.

M = Fd

where M is the moment, F is the force,

and d is the distance between the force and the fulcrum

F*L_F = R*L_R

where F is the force, L_F is the distance between the application and the fulcrum

R is the resistance, and L_R is the distance between the resistance and the fulcrum

Class 1: The fulcrum is located between the applied force and the load

Class 2: The load is located between the fulcrum and the force

Class 3: The force is located between the fulcrum and the load