15.2 : Characteristics of Simple Harmonic Motion

The key characteristic of the simple harmonic motion is that the acceleration of the system and, therefore, the net force are proportional to the displacement and act in the opposite direction to the displacement. Additionally, the period and frequency of a simple harmonic oscillator are independent of its amplitude. For example, diving boards move faster or slower based on their thickness. A stiff, thick diving board has a large force constant, which causes it to have a smaller period, while a thin diving board moves faster and with a higher period. The period of a simple harmonic oscillator is also affected by its mass. A heavier person on a diving board bounces up and down slower than a person with a relatively lighter weight.

The simple harmonic motion of a system results in a sine and cosine waveform. As the amplitude changes, the maxima and minima of the curve also change, but the period and frequency remain unaffected. By altering the phase angle, the curve shifts toward the right for negative values and toward the left for positive values. In general, negative phase angle values shift the standard cosine curve rightward.