Furthermore, the velocity and the acceleration of the object are also described by sine or cosine terms. A close relationship exists between simple harmonic motion and circular motion. A circular path may therefore be considered the path of an object subjected to two restoring forces acting at right angles to each other. Elliptical motion may also be considered as the result of two separate perpendicular harmonic motions. Although describing circular or elliptical motion by means of two separate harmonic motions is usually unnecessary, this is often the simplest way to treat more intricate patterns, particularly those known as Lissajous Figures.
Harmonic motion is characterized by symmetric movement about the equilibrium position.
If each maximum displacement is instead slightly less than the previous one, the motion is said to be damped. Damping is the dissipation of the kinetic energy of the oscillator and causes vibrations to die out. Energy-absorbing devices, which may be something as simple as rubber cushions, are useful wherever vibrations are undesirable.