Angular acceleration

The angular acceleration (symbol: α ) denotes the variation of the angular velocity of a rotating object. It is a vector quantity. Mathematically speaking, it is the derivative of the angular velocity with respect to time. In many cases, where the direction of the rotation axis in the reference system does not change, is sufficient the use of scalar as an amount of the vector.

The SI unit of angular acceleration rad/s2 ( radians per second squared).

The angular acceleration is to be distinguished from a tangential point, which represents the time derivative of the line speed according to the time.

Between the torque and the angular acceleration, the relationship is the rigid body with moment of inertia:

In vector form, the change of the angular momentum is equal to the external torque ( Euler's equation):

Therefore, angular accelerations play in the art including a major role in pulley drives, shafts, electric motors, centrifuges (eg drum of the washing machine or dryer) and wheels of vehicles. If the drive causes an excessive angular acceleration, the maximum torque can be exceeded, and it may for example come to slip a drive belt or damage to or destruction of a wave.

In astronomy, the angular acceleration of a planet is related to its sun with the face set (second Kepler 's law). The planet approaches the central body increases its angular velocity.

• Kinematics
• Physical size style