An object in equilibrium is at rest. It is not moving (or "translating") and it is not rotating.

There are two conditions of equilibrium.

That a body is not moving (or "translating") means the sum of the forces is zero,

F = 0

That a body is not rotating means the sum of the torques is zero,

We can also write this Second Condition of Equilibrium as

A torque is a "rotational force" or the rotational equivalent of a force,

torque = moment arm x force

The behavior of a material as it is deformed is described by a modulus,



Deformation of Solids

Return ToC, Static Equilibrium

(c) Doug Davis, 2001; all rights reserved