Equilibrium of Rigid Bodies

The conditions for equilibrium, the centre of gravity and the stability of rotational equilibrium, followed by stress, strain and the elastic behaviour of real materials. Diagram driven throughout, which makes it easy to follow where each force acts.

M. F. McGraw, Austin Community College

Defines forces and moments as vectors, builds the free body diagram from them, and then uses the equations of static equilibrium to solve for reaction forces and moments. The worked cases come from optical mounting, where a millimetre of unwanted motion matters.

J. H. Burge, University of Arizona

Works the lever law and its generalised form, then applies both to a suspended rod, a person standing on a hill and the forces inside a knee. An appendix proves that the torques about any two points are equal for a body in static equilibrium.

Peter Dourmashkin

A tight summary of the equilibrium conditions for a rigid object, stated first as vector equations and then reduced to the two dimensional case you will actually use. Almost every page is a solved problem rather than theory.

David Murdock

A single lecture on the force conditions needed to keep a structure in equilibrium, and on how to isolate the system before writing a single equation. It argues that the free body diagram is the most important step in any mechanics problem, then shows why.

University of Technology