Two 3 kg uniform semicircular plates are attached by pins to

Two 3 kg uniform semicircular plates are attached by pins to the 2 kg uniform sleder rod AB. Assume that the plates roll without slip on the level ground. Rod AB is displaced 10mm to the right and given a velocity of 5mm/s to the right

Q: Determine the period of small oscillations of the system. Rod AB is displaced 10mm to the right and given a velocity of 5mm/s to the right