When excited electrons decay to ground state, hydrogen emits along distinctive line near the visible red. An astronomer observes what appear to be hydrogen emission lines from a distant star but they are in the infrared spectral band. She concludes .

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?