Work and potential energy

Abstract

The sum of the elementary work due to the application of forces F _i at points M _i of a system undergoing virtual displacements δr _i of these points from their positions at a fixed time instant is given by

$$ \delta 'W = \sum\limits_{i = 1}^N {F_i } \cdot\delta r_i .$$

(5.1.1)

The notation δ’ is used to indicate that we are dealing with an infinitesimal quantity which is not a variation of the quantity W.