Two disks are mounted (like a merry-go-round) on low-friction bearings on the same axle and can be brought together so that they couple and rotate as one unit. The first disk, with rotational inertia 3.30 kg ∙ m about its central axis, is set spinning counterclockwise at 450rev/min. The second disk, with rotational inertia 6.60 kg ∙ m about its central axis, is set spinning counterclockwise at 900rev/min. They then couple together.
(a) What is their angular speed after coupling? If instead the second disk is set spinning clockwise at 900 rev/min, what are their
(b) Angular speed and
(c) Direction of rotation after they couple together?