A ball of mass m is suspended above the center of the rotating platform on the elastic spring with stiffness k and initial (non-stretched) length l0 as shown. The opposite end of the spring is attached to the vertical pole fixed on axis of the platform. The platform starts to rotate with angular velocity ω. What is the angle α that the spring makes with the vertical? Consider all values of the angular velocity, from ω=0 to ω=inf and find the conditions on ω when the angle α >0 and when α =0.