Angular acceleration is a vector whose magnitude is defined as the change in angular velocity in unit time.
It is in in SI unit.
Analogous to translational acceleration, , angular acceleration has the defining formula:
in which represents an instantaneous change in angular velocity,which takes place in , a short flitting time.
Equivalently, think about the limiting case:
Relationship with Constant Torque
The angular acceleration of an fixed-axis-object is proportional to the net torque applied.
in which is the Moment of Inertia of the object.
When an rotation has constant angular acceleration , the angle displacement covered in a given time is given by an equation that is strikingly similar to the equation for displacement under constant acceleration.
in which is the angular velocity at the beginning of the time period
in which case the angular velocity at the beginning is "zero"
in which is the angular velocity at the end of the time period