Consider two massless rods of length l=15 cm, each suspended by one end and able to rotate freely about their suspension points. These suspension points are at the same height, separated by a distance d=30 cm. The free ends of the rods are connected by a rod of mass m=300 g and length d. What is the period of small oscillations if the system is displaced within the plane containing the rods? The system is in a gravitational field with acceleration g.