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Engineering Statics: Open and Interactive

Chapter 5 Rigid Body Equilibrium

This chapter will investigate the equilibrium of simple rigid bodies like your book, phone, or pencil. The important difference between rigid bodies and the particles of Chapter 3 is that rigid bodies have the potential to rotate around a point or axis, while particles do not.
For rigid body equilibrium, we need to maintain translational equilibrium with
\begin{equation} \sum \vec{F}=0\tag{5.0.1} \end{equation}
and also maintain a balance of rotational forces and couple-moments with a new equilibrium equation
\begin{equation} \sum \vec{M}=0\text{.}\tag{5.0.2} \end{equation}