Explanation:
To find the angular acceleration of the electric fan, we can use the formula:
angular acceleration = (final angular velocity - initial angular velocity) / time
Here, the initial angular velocity is 600 rev/min, the final angular velocity is 200 rev/min, and the time is 4.00 s.
Substituting these values in the formula, we get:
angular acceleration = (200 rev/min - 600 rev/min) / 4.00 s
angular acceleration = -400 rev/min / 4.00 s
angular acceleration = -100 rev/min^2
Therefore, the angular acceleration of the electric fan is -100 rev/min^2.