Simple harmonic motion

Summary

Simple harmonic motion is periodic motion along a line in which the position is a sine function of time, $x(t) = A \cos(\omega t + \varphi)$. It is the motion of the harmonic oscillator, driven by a restoring force proportional to the displacement. Its period does not depend on the amplitude. Small vibrations near a stable equilibrium are approximately of this kind, which makes it the basic model of all oscillations. See the definition.