Basic Terms Associated with SHM

Displacement

It is the distance of the harmonic oscillator from its mean (or equilibrium) position at a given instant.

Amplitude

It is the maximum displacement of the oscillator on either side of its mean position.

Time period

It is the time taken by the oscillator to complete one oscillation.

Frequency

It is the number of oscillations completed by an oscillator in one second. It is denoted by v. The SI unit of frequency is hertz (Hz). Since v is the number of oscillations per second, the time taken to complete one oscillation is 1/v.

T =1/v 

Phase (φ)

It is the angle whose sine or cosine at a given instant indicates the position and direction of motion of the oscillator. It is expressed in radians.

Angular Frequency (ω)

It describes the rate of change of phase angle. It is expressed in radian per second. Since phase angle changes from 0 to 2π radians in one complete oscillation, the rate of change of phase angle is

ω = 2π/T = 2πv or ω = 2πv