The disk with moment of inertia I = 3 kg-m2 rotates about a fixed shaft and is attached to...

The disk with moment of inertia I = 3 kg-m2 rotates about a fixed shaft and is attached to a torsional spring with constant k = 20 N-m/rad. At t = 0. the angle θ = 0. the angular velocity is dθ/dt = 4 rad/s, and the disk is subjected to a couple M (t) = 10 sin 2t N-m. Determine θ as a function of time.