A device for measuring the moment of inertia of an object is shownin the figure below. The circular platform is attached to aconcentric drum of radius R, and are free to rotate abouta frictionless vertical axis. The string that is wound around thedrum passes over a frictionless and massless pulley to a block ofmass M. The block is released from rest, and the timet1 it takes for it to drop a distanceD is measured. The system is then rewound, the object whose moment of inertia I we wish to measure is placed onthe platform, and the system is again released from rest. The timet2 required for the block to drop the samedistance D then provides the data needed to calculateI. Use R = 8 cm,M = 2.7 kg, D =1.9 m, t1 =4.1 s, and t2 =7.0 s.
a) Find the moment of inertia of the platform-drum combination.
b) Using t2 = 7.0 s,find the moment of inertia of the platform-drum-object combination.
c) Use your results for Parts (a) and (b) to find the moment ofinertia of the object.