A lever works on the principle of moments (short time). For an ideal lever, it is imagined that the lever is light weight (weightless) and frictionless. It has been practically based that when two same forces proceeding in different (opposite) directions, i.e., clockwise and counterclockwise, are applied to a uniform lever at same distances from the fulcrum, they oppose each other and found a state of equilibrium in the lever.

In the stability position of the lever, by the principle of moments (short time),

Moment of load to the fulcrum = Moment of the effort to the fulcrum.