The Angular velocity reference article from the English Wikipedia on 24-Jul-2004
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Angular velocity

Helping orphans the way you would do it
Angular velocity describes the speed of rotation. The direction of the angular velocity vector will be along the axis of rotation and towards the viewerEnlarge

Angular velocity describes the speed of rotation. The direction of the angular velocity vector will be along the axis of rotation and towards the viewer

Angular velocity is the vector physical quantity that represents the rotation of a spinning body. It is usually represented by the symbol Ω or ω. The magnitude of the angular velocity is the angular speed (or angular frequency) and is denoted by ω. The line of direction of the angular velocity is given by the axis of rotation, and the right hand rule indicates the positive direction, namely:

If you allow the fingers of your right hand to follow the direction of the rotation, then the direction of the angular velocity vector is indicated by your right thumb.

In SI units, angular velocity is measured in radians per second, (rad/s), although a direction must also be given. The dimensions of angular velocity are T−1, since radians are dimensionless.

With constant angular acceleration, the angular velocity conforms to the rotational equations of motion, equivalent to the standard linear equations of motion under constant linear acceleration.