Given:
initial angular speed, [tex]\omega _{i}[/tex] = 21.5 rad/s
final angular speed, [tex]\omega _{f}[/tex] = 28.0 rad/s
time, t = 3.50 s
Solution:
Angular acceleration can be defined as the time rate of change of angular velocity and is given by:
[tex]\alpha = \frac{\omega_{f} - \omega _{i}}{t}[/tex]
Now, putting the given values in the above formula:
[tex]\alpha = \frac{28.0 - 21.5}{3.50}[/tex]
[tex]\alpha = 1.86 m/s^{2}[/tex]
Therefore, angular acceleration is:
[tex]\alpha = 1.86 m/s^{2}[/tex]