An Etymological Dictionary of Astronomy and Astrophysics
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A measure of the angular displacement per unit time. Of a particle traveling on a circular path or a rotating body, the ratio of the angle traversed to the amount of time it takes to traverse that angle: ω = dθ/dt. For a rigid body, all lines in it rotate through the same angle in the same time, and the angular velocity is the characteristic of the body as a whole. The angular velocity is related to the linear velocity by the equation v = rω, where r is the distance of the point from the rotation axis. → vector angular velocity.

→ angular; → velocity.

The angular velocity of a point in a circular orbit around a central mass. It is given by: Ω_K = (GM/r³)^1/2, where G is the → gravitational constant, M is the mass of the gravitating object, and r is the radius of the orbit of the point around the object.

→ Keplerian; → angular; → velocity.

Of a rotating body, a vector of magnitude ω (→ angular velocity) pointing in the direction of advance of a right-hand screw which is turned in the direction of rotation.

→ vector; → angular; → velocity.