Simple harmonic motion (SHM) is a type of periodic motion where an object oscillates back and forth around an equilibrium position under the influence of a restoring force that is proportional to its displacement from the equilibrium position. Examples of simple harmonic motion include the motion of a pendulum, a mass on a spring, or a vibrating guitar string. The displacement of the object from its equilibrium position at any given time can be described by a sinusoidal function such as sine or cosine. The key characteristics of SHM include a constant period (the time for one complete oscillation) and a sinusoidal displacement-time graph.
