12. 1 motion of an object attached to a spring. Equilibrium position (x=0) is defined as the position in which a spring is neither stretched nor compressed. Fs is called a restoring force because it is always directed towards the equilibrium position and opposite the displacement. An object moved with simple harmonic motion whenever its acceleration is proportional to its position and is oppositely directed to the displacement of equilibrium. The period, t, of the motion is the time interval required to go through one full cycle of motion. The inverse of the period is called the frequency, f. This represents the oscillations the particle undergoes per unit time interval. Units of frequency are cycles per second, or hertz. The period and frequency depend only on the mass of the particle and the force constant of the spring and not on the parameters of the motion, such as a or phi. In a spring, it constantly converts between kinetic energy.
