The two Disks are mounted on low-friction bearings on the similar axle and can be brought altogether so that they couple and rotate as one unit. The primary disk, with rotational inertia of around 3.5 kg•m2 about its central axis, is set spinning at 300 rev/min. The second disk, having rotational inertia 6.2 kg•m2 about its central axis, is set spinning at 700 rev/min in the similar direction as the first. They then couple altogether.
(i) Determine their rotational speed after coupling?
(ii) If rather the second disk is set spinning at 700 rev/min in the direction opposite the first disk's rotation, determine their rotational speed and direction after coupling?