The angular velocity of a flywheel change from `6` rad `s^(-1)` to `18` rad `s^(-1)` in `6` seconds. Calculate its angular acceleration.

Explanation

To solve the problem of calculating the angular acceleration of the flywheel, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the given values:**
- Initial angular velocity (\( \omega_i \)) = 6 rad/s
- Final angular velocity (\( \omega_f \)) = 18 rad/s
- Time taken (\( t \)) = 6 seconds
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