Equilibrium

Abstract

A body is in equilibrium when the forces acting on it balance each other so that it either remains at rest or, if it is moving, remains in a state of uniform motion (i.e. constant speed in a straight line). To understand equilibrium we need to recognise that forces can influence the motion of a body in two ways: they can affect its translational motion from one place to another (with all its parts moving in the same direction) and they can affect its rotation.