Angular velocity $\vec{\omega}$ is an axial vector, which means its direction is along the axis of rotation (determined by the right-hand rule). Angular acceleration $\vec{\alpha}$ is the time rate of change of angular velocity ($\vec{\alpha} = \frac{d\vec{\omega}}{dt}$). For a body moving along the circumference of a circle with a fixed axis of rotation, the change in angular velocity only occurs in its magnitude, while its direction remains along the axis. Therefore, the angular acceleration is also directed along the axis of rotation .