If the spring has a torsional stiffnessk = 300 N · m/rad and is unwound when θ = 90°, dete...

If the spring has a torsional stiffnessk = 300 N · m/rad and is unwound when θ = 90°, determine the angle for equilibrium if the sphere has a mass of 20 kg. Investigate the stability at this position. Collar C can slide freely along the vertical guide. Neglect the weight of the rods and collar C.