This document defines beams and support reactions. It discusses statically determinate beams and explains that support reactions can be determined using equilibrium conditions alone for these beams. The document outlines different types of beam supports including simple, pinned, roller, and fixed supports. It also defines types of beams such as simply supported, cantilever, overhang, and continuous beams. Finally, it discusses determining support reactions for statically determinate beams using equilibrium conditions and introduces the concept of virtual work.