Free vibration is where there is no externally applied vibrating forcing.
In free vibration, energy will remain the same, and energy is not added or removed from the body.
The body keeps vibrating at the same amplitude.
The solution to a free vibration is usually roughly sinusoidal.
Example oscillations of object connected to a horizontal spring, the sound produced by turning fork in a short distance.
There are three types of free vibrations 7.1 Longitudinal vibrations: The disc moves parallel to the axis. 7.2 Transverse vibration: The disc moves perpendicular to the axis. 7.3 Torsional vibrations: The disc moves a circle about the axis.