Harmonic motion describes periodic motion wherein the displacement path is comprised of one or more symmetric vibratory motions about an equilibrium position. A particular form of harmonic motion is called simple harmonic motion.

For objects undergoing simple harmonic motion, the velocity of the displaced object constantly changes, oscillating just as does the magnitude of displacement (as measured from equilibrium). When the objectüs displacement is maximum, the velocity is zero and when there is zero displacement the objectüs velocity is maximum. With simple harmonic motion, acceleration also oscillates.

A mass hanging from a coiled spring will exhibit simple harmonic motion. When disturbed from equilibrium, it will it will cyclically move upwards and downwards in a sinusoidal, oscillating motion. Robert Hooke first formulated the law used to describe such simple harmonic motion. Hooke's law states that the force a spring exerts on a body that is...