Simple harmonic motion is the motion of a simple harmonic oscillator, a motion that is neither driven nor damped. The motion is periodic, as it repeats itself at standard intervals in a specific manner - described as being sinusoidal, with constant amplitude. It is characterized by its amplitude (which is always positive), its period which is the time for a single oscillation, its frequency which is the number of cycles per unit time, and its phase, which determines the starting point on the sine wave. The period, and its inverse the frequency, are constants determined by the overall system, while the amplitude and phase are determined by the initial conditions (position and velocity) of that system. (Wikipedia, 2008)

A general equation describing simple harmonic motion is x=Acos(2pft+f), where x is the displacement, A is the amplitude of oscillation, f is the frequency, t is the elapsed time, and f is the phase of oscillation.

To create a simple model of simple harmonic motion, I have created an animated VB program which used the equation x=Acos(wt), and I have assigned a value of 500 to A and a value of 50 to w. In this program, the circle which I have inserted into the form will oscillate from left to right, reaching maximum speed at the middle of the path.