ABSTRACT
Forces can be grouped into two broad categories: surface forces and body forces. Surface forces are those that act over a surface (as the name implies), and result from direct physical contact between two bodies. In contrast, body forces are those that act at a distance, and do not result from direct physical contact of one body with another. The force of gravity is the most common type of body force. In this chapter we are primarily concerned with surface forces, the effects of body forces (such as the weight of a structure) will be ignored.
