일반물리학 1 — Rotation: Problem 15

15 Starting from rest, a wheel has constant \(\alpha = 3.0 \text{ rad/s}^2\). During a certain \(4.0 \text{ s}\) interval, it turns through \(120 \text{ rad}\). How much time did it take to reach that \(4.0 \text{ s}\) interval?