Two identical piano wires have a fundamental frequency of 494 hz when kept under the same tension. what fractional increase in the tension of one wire will lead to the occurrence of 5 beats/s when both wires oscillate simultaneously?

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?