A single force that can replace a number of coplanar forces acting on a rigid body, producing the same effect as all those forces combined, is known as the:

In standard assumptions made for plane truss structures, the connections between members are assumed to be joined by:

The coefficient of friction is theoretical value of _____ for ideal, perfectly smooth surfaces.

In the analysis of structures by the principle of Virtual Work, which of the following forces are assumed to do work and are not omitted?