Problem: Two solid disks are both spinning on the same frictionless, vertical axle. The upper disk is spinning clockwise at 450 rpm (rev/min), and the lower disk is spinning at 280 rpm (rev/min), counterclockwise. The upper disk is released, and it falls a few centimeters onto the lower disk. After the two disks couple together, their final angular velocity is 65 rpm, counterclockwise. If the moment of inertia of the lower disk is 4.8 kg m2,

Part A: What is the moment of inertia of the upper disk? Apply the angular momentum conservation principle.

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