When the displacement of a mass on a spring is 12 A, what percentage of the energy is kinetic energy? At what displacement, as a fraction of A, is the energy half kinetic and half potential?

Why does the equilibrium position of the spring change when a mass is added to the spring? will the mass oscillate around the new equilibrium position of the spring or the previous position without a mass attached to the spring? if the equilibrium position of the spring changes by 20 cm (assuming no initial mass) when a mass is added to the spring with constant 4.9 kg/s^2, what is the mass of the object attached to the spring?