Angular acceleration : The time rate of change of angular velocity of a particle performing circular motion is called the angular acceleration.
(i) If \( \delta \vec \omega\) is the change in angular Velocity in a short time interval St, the angular acceleration
(ii) The direction of \(\vec{a}\) is the same as that of \(d\vec{\omega}\). We consider the case where a change in \(\vec\omega\)arises due to a change in its magnitude only. If the particle is speeding up, i.e., ω is increasing with time, then \(\vec{a}\) is in the direction of \(\vec\omega\). If the particle is slowing down, i.e., ω is decreasing with time, then \(\vec{a}\) is directed opposite to \(\vec\omega\)
Angular acceleration \(\vec{a}\) when \(\vec\omega\) is
(a) increasing (b) decreasing
(iii) If the angular speed changes from ω1 to ω2 in time f, the magnitude (α) of the average angular acceleration is
α = \(\frac{\omega_2- \omega_1}t\)
