The uniform link AB, has a mass of 3 kg and is pin connected at both of its ends. The rod...

The uniform link AB, has a mass of 3 kg and is pin connected at both of its ends. The rod BD, having negligible weight, passes through a swivel block at C. If the spring has a stiffness of k = 100 N/m and is unstretched when θ = 0°, determine the angle θ for equilibrium and investigate the stability at the equilibrium position. Neglect the size of the swivel block.