A thin, round disk made of acrylic plastic (density is 1.1 g/cm) is 20 cm in diameter and 3 cm thick (see figure below). A very small hole is drilled through the disk at a point 8 cm from the center. The disk is hung from the hole on a nail and set into simple harmonic motion with a maximum angular displacement (measured from vertical) of 7. Calculate the period of the motion. 8 cm 1701 A hole is drilled through a thin, round disk of mass M and radius R = 0.10 m. The hole is located h = 0.08 m from the center of mass of the disk. The disk is hung on a nail and set into simple harmonic motion. The period of a physical pendulum is related to the moment of inertia of the pendulum. Since the center of mass of the disk is located a distance h from the pivot point, we will need to use the parallel-axis theorem. As a reminder, the moment of inertia of a thin disk is -MR.