Damped harmonic motion

Damped harmonic motion is similar to simple harmonic motion, i.e the period is constant and the frequency is equal to 1/Period. However, the amplitude decreases due to the affect of a resistive force. The motion can still be modelled mathematically by finding the governing differential equation and solving.

For example:

A mass of 5 kg is attached to a string of natural length 2 m, with a modulus of elasticity of 20 N is set oscillating, and is resisted by a force of 2 m × its velocity (v).