The document discusses simple harmonic motion (SHM) and presents the equation of motion for an object undergoing SHM. It defines key terms like equilibrium position, spring constant, angular frequency, amplitude, phase, period, and frequency. Examples are given of finding the equation of motion for objects attached to springs given their mass, spring constant, initial position and velocity. The equation of motion is derived from Newton's second law as a second order differential equation. Its general solution is presented in the form of trigonometric functions with constants determined by the initial conditions.