Because the simple harmonic vibration is equivalent to the circular motion projected on the diameter, the angular frequency ω is introduced to describe the simple harmonic vibration.

The motion of an object (particle) on both sides of the center position is called mechanical vibration. An object can move back and forth around an equilibrium position, and it must be subjected to the force that enables it to return to the equilibrium position, that is, the restoring force. Restoring force is a force named after effect, which can be a force or a component of a force, or a resultant force of several forces.

Extended data:

Vibration can also be represented by vectors. The vector rotates counterclockwise with equal angular velocity ω. The modulus of displacement vector is amplitude a, the modulus of velocity vector is amplitude ωA of velocity, and the modulus of acceleration vector is amplitude ω2A of acceleration.

The velocity vector is 90 before the displacement vector and the acceleration vector is180 before the displacement vector. If the particle is not in the equilibrium position at the beginning of vibration, its displacement can be expressed by the following formula: x(t)=Asin(ωt+ψ).