Authors' Homepages:   Anthony Bedford  
Wallace Fowler  
Chapter 10: Internal Forces and Moments
"We began our study of equilibrium by drawing free-body diagrams of individual objects to determine
unknown forces and moments acting on them. In this chapter we carry this process one step further
and draw free-body diagrams of parts of individual objects to determine internal forces and moments.
In doing so, we arrive at the central concern of the structural design engineer: It is the forces which an
object that determine whether it will support the external loads to which it is subjected."