Angular Acceleration:
Measures how fast an object's rate of rotation is speeding up or slowing down.

Definition:

* The angular acceleration of all parts of a rotating body is the same, independent of how close or how far each part is from the axis of rotation.

Units:
SI: rad/s²

Others Units: rev/s², deg/sec/sec

Uniform angular acceleration

Angular Velocity and Acceleration
A constant force is applied to a frictionless disk giving the disk a constant angular acceleration. The tangential velocity of several points on are displayed.