A periodic movement is one in which its characteristic magnitudes are repeated at regular intervals of time. A periodic movement is oscillatory if it covers the trajectory in both directions. An oscillatory movement is vibratory if its trajectory is rectilinear and it is centred on the origin.

A HARMONIC movement is a vibratory movement in which position, velocity and acceleration can be described with sinusoidal (sine or cosine) functions. Of all harmonic movements, the simplest one is the Simple Harmonic Movement which is the one we will be referring to from now on.  

A SIMPLE HARMONIC MOVEMENT is one in which the position of the body is given by a function of the following type.

By clicking on next you will see the meaning of each one of the magnitudes which appear in this equation