Two flywheels, one with moment of inertial 240kgm^2 and one with moment of inertial 150kgm^2 turn on the same shaft.

Two flywheels, one with moment of inertial 240kgm^2 and one with moment of inertial 150kgm^2 turn on the same shaft. The First wheel is fixed on the shaft, the second one is connected by a clutch, so that it can be made to turn either with the first or independently of it. Initially the first wheel is turning at 30rad/s. The second is at rest, the clutch is then operated, so that wheels turn together, what is the common angular speed.