In physics, angular frequency "ω" (also referred to by the terms angular speed, circular frequency, orbital frequency, radian frequency, and pulsatance) is a scalar measure of rotation rate. It refers to the angular displacement per unit time (for example, in rotation) or the rate of change of the phase of a sinusoidal waveform (for example, in oscillations and waves), or as the rate of change of the argument of the sine function.Angular frequency (or angular speed) is the magnitude of the vector quantity angular velocity. One turn is equal to 2π radians, hence where: