Editing Rotational frequency (section)

==Regression analysis==
Rotational frequency can measure, for example, how fast a motor is running. ''Rotational speed'' is sometimes used to mean [[angular frequency]] rather than the quantity defined in this article. Angular frequency gives the change in [[angle]] per time unit, which is given with the unit [[radian per second]] in the SI system. Since 2π radians or 360 degrees correspond to a cycle, we can convert angular frequency to rotational frequency by
<math display=block>\nu = \omega/2\pi ,</math>
where
* <math>\nu\,</math> is rotational frequency, with unit cycles per second
* <math>\omega\,</math> is angular frequency, with unit radian per second or degree per second

For example, a [[stepper motor]] might turn exactly one complete revolution each second.
Its angular frequency is 360 [[degree (angle)|degrees]] per second (360°/s), or 2π [[radian]]s per second (2π&nbsp;rad/s), while the rotational frequency is 60&nbsp;rpm.

Rotational frequency is not to be confused with [[Speed#Tangential speed|tangential speed]], despite some relation between the two concepts. Imagine a merry-go-round with a constant rate of rotation.  No matter how close to or far from the axis of rotation you stand, your rotational frequency will remain constant. However, your tangential speed does not remain constant.  If you stand two meters from the axis of rotation, your tangential speed will be double the amount if you were standing only one meter from the axis of rotation.