A thin metal disk with mass 2.00 X 10-3 kg and radius 2.20 cm is attached at its center to a long fiber (?Fig. E14.42?). The disk, when twisted and released, oscillates with a period of 1.00 s. Find the torsion constant of the fiber.

Solution 42E A thin metal disk is attached at its center to a long fiber ,the disk when twisted and released oscillates with a time period of 1 s along the z axis of the disk. Torsion constant of the fiber can be found by first finding the Moment of Inertia of the disk (I) about the z axis. Step 1 of 2: Moment of Inertia (I) of the disk along the z axis can be calculated using the relation 1 2 I = 2 × m × R 2 = 1× (2 × 10 ) × (2.2 × 10 )2 2 I =4.84× 10 7 kg m 2