Angular Acceleration

The angular acceleration $\boldsymbol{\alpha}$ is defined as the time Derivative of the Angular Velocity $\boldsymbol{\omega}$,

$$\boldsymbol{\alpha}\equiv{d\boldsymbol{\omega}\over dt}={d^2\theta\over dt^2}\hat{\bf z}={{\bf a}\over r}.$$

See also Acceleration, Angular Distance, Angular Velocity