The motion of a body is said to be oscillatory motion if it moves to and fro about a fixed point after regular intervals of time. The fixed point about which the body oscillates is called mean position or equilibrium position. (ii) The acceleration of the particle is always directed towards a fixed point on the line.
The three main types of simple harmonic motion in physics are: Free Oscillation, Forced Oscillation and Damped Oscillations.
It is the phenomenon wherein an external vibrating system causes the oscillation of another system with a higher amplitude at a particular frequency. The frequency at that particular resonance level is known as a resonant frequency.