ABSTRACT
A very important component in any machinery is a shaft that rotates and is supported at two ends by bearings. This shaft may have a disc mounted on it, which could be like a gear, pulley, and so on. The dynamics of the shaft at different rotating speeds is very crucial to designers, because the loads at the bearings may vary, and oscillations in the shaft may occur which may lead to conditions of instability. Conditions of resonance may occur at certain operating speeds of the shaft. These issues will be briefly addressed in this chapter.
