# Angular Speed

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## angular speed

[′aŋ·gyə·lər ′spēd]
(mechanics)
Change of direction per unit time, as of a target on a radar screen, without regard to the direction of the rotation axis; in other words, the magnitude of the angular velocity vector. Also known as angular rate.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

## Angular Speed

a quantity that characterizes the rate of rotation of a rigid body. If a body rotates uniformly about a fixed axis, its angular speed is ω = Δφ/Δt, where Δφ is the increment of the rotation angle φ in the time interval Δt. In general, angular speed is the magnitude of the vector quantity angular velocity and is equal to the ratio of the elemental rotation angle dφ and the corresponding elemental time interval dt—that is, ω = dφ/dt. The angular velocity vector is aligned with the rotation axis in the direction from which the rotation of the body is seen as counter-clockwise (in a right-handed coordinate system). Angular speed has the dimension T–1, where T is time. In English the term “angular velocity” is sometimes used synonymously with “angular speed.”