Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. In physics, simple harmonic motion (SHM) is the motion of a simple harmonic oscillator, a motion that is neither driven nor damped. A body in simple harmonic motion experiences a single force which is given by Hooke''s law; that is, the force is directly proportional to the displacement x and points in the opposite direction. The motion is periodic: the body oscillates about an equilibrium position in a sinusoidal pattern. Each oscillation is identical, and thus the period, frequency, and amplitude of the motion are constant.