Complex harmonic motion

Unlike simple harmonic motion, which is regardless of air resistance, friction, etc., complex harmonic motion often has additional forces to dissipate the initial energy and lessen the speed and amplitude of an oscillation until the energy of the system is totally drained and the system comes to rest at its equilibrium point.

Damped harmonic motion is a real oscillation, in which an object is hanging on a spring.

Because of the existence of internal friction and air resistance, the system will over time experience a decrease in amplitude.

An object or a system is oscillating in its own natural frequency without the interference of an external periodic force or initial motion.

Varying lengths and masses of the two arms can make it hard to identify the centers of the two rods.

[7] The image shows a marine clock with motor springs and double pendulum sheel.