Vibrations of Simple Systems:

Vibration is a periodic motion that repeats itself after a specific interval of time. This time interval is termed as the period of vibration which is generally measured in seconds. Each repetition of motion is termed a cycle. The frequency of the vibration is the reciprocal of the period.

Furthermore, vibrations may be grouped as free and forced vibration. In free vibrations, after this is begun by external disturbing force, which after displacing the body from its equilibrium position, ceases to act on the vibrating body.

In forced vibrations, the disturbing forces continue to act on the body at periodic intervals.

A simple mechanical system contains three basic components or elements: spring, mass and dash pot. Mass is an inertial element, spring provides restoring force and is supposed to conserve energy, and dash pot, a damping element, is connected with dissipative action, attained through dry friction or viscous shearing.