To use free-body diagrams to determine internal axial forces and to learn how to calculate axial normal stresses. When a theoretical cutting plane is passed through an axially loaded prismatic bar, perpendicular to the longitudinal axis of the bar, and one side is analyzed as a free-body diagram, there is a uniformly distributed force acting on the bar's cross section. This uniform force distribution represents the action of the part of the bar removed on the part remaining and must exist to maintain equilibrium. The force distribution is an intensity of the force, or the force per unit area at the cross section, called the normal stress. Is is "normal" because it acts perpendicular to the section and it is a "stress" because it is an intensity of force distributed over a section (or area).The axially loaded bar is fixed at A and loaded as shown. Draw a free-body diagram and determine the support reaction at A. On paper, draw a free-body diagram of the bar and determine the reaction at A for the bar to be in equilibrium. Assume that the unknown reaction at A acts in the negative x direction.