Any periodic motion that repeats itself at regular time interval and continues for long time is assigned a ‘frequency’ of repetition of motion. We say that one repetition means occurrence of motion once. The number of times the motion is repeated per unit time is known as the frequency of the motion.
If T be the periodic time of a motion, the number of repetitions in unit time is 1/T. Hence frequency= 1/T.
Frequency is denoted by n, f or v. Then
v = 1/T
The S.I. unit of frequency is Hertz, denoted by Hz.
1 Hz = 1 cycle per second (1 cps)
Frequency is a feature of any periodic motion, not only of oscillations. Frequency is also called ‘linear frequency’. Angular frequency is defined as 2π time the linear frequency. It is denoted by ω(unit :s –1):
ω = 2πv
(Note that ω here is not angular velocity)
