# Moment (physics)

In physics, moment of force (often just moment) is a measure of a force's tendency to cause a body to rotate about a specific point or axis.

In this concept the moment arm, the distance from the axis of rotation, plays an important role. The lever, pulley, gear, and most other simple machines create mechanical advantage by changing the moment arm. The SI unit for moment is the newton meter (kgm²/s² or Nm).

Formula for moment:

${\displaystyle {\text{Moment}}={\text{Force}}\times {\text{Perpendicular distance}}}$

The Principle of Moment states that when a system is in equilibrium the sum of its CLOCKWISE MOMENTS equals the sum of its ANTICLOCKWISE MOMENTS.

Some examples where moments (turning effect) are applied involve levers, like seesaws, opening and closing doors, nutcrackers, can openers, and crowbars.

A lever is a simple machine in which one force called the effort is used to overcome another force called the load.

In physics, a moment is a combination of a physical quantity and a distance.

## History of moment

The principle of moments is derived from Archimedes' discovery of the operating principle of the lever. In the lever one applies a force, in his day most often human muscle, to an arm, a beam of some sort. Archimedes noted that the amount of force applied to the object, the moment of force, is defined as M = rF, where F is the applied force, and r is the distance from the applied force to object.