You are most likely familiar with several examples of periodic motion,such as the oscillations of an object on a spring,the motion of a pendulum,and the vibrations of a stringed musical instrument.Numerous other systems exhibit periodic behavior.For example,the molecules in a solid oscillate about their equilibrium positions; electromagnetic waves,such as light waves,radar,and radio waves,are characterized by oscillating electric and magnetic field vectors; in alternating-current circuits,such as in your household electrical service,voltage and current vary periodically with time.In
this chapter,we will investigate mechanical systems that exhibit periodic motion.