2.4. Angular acceleration

In case of uneven movement does not remain constant. The value characterizing the rate of change of the angular velocity is called the angular acceleration and is equal to:

(2.5)

In the case of rotation of the body around
fixed axis change vector due only to a change in its numerical value. With this vector angular acceleration is directed along the axis of rotation in the same direction as with accelerated rotation and in slow motion in the opposite direction. (fig. 2.3 a), b))