20 cubic inches of a gas with an absolute pressure of 5 psi is compressed until it’s press reaches 10 psi. what is the new volume of the psi and assuming there’s no change in temperature

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?