A metal rod of length L and mass m is pivoted at one end. A thin disk of mass M and radius `R (lt L)` is attached at its center to the free end of the rod.

Consider two ways the disc is attached : (case A). The disc is not free to rotate about its centre and (case B) the disc is free to rotate about its centre. The rod disc system perform SHM in vertical plane after being released from the same displaced position. Which of the following statement(s) is (are) true

Options

A. Restoring torque in case A = Restoring torque in case B
B. Restoring torque in case A `lt` Restoring torque in case B
C. Angular frequency for case A `gt` Angular frequency for case B
D. Angular frequency for case A `lt` Angular frequency for case B

Answer

A, D