How long would it take light from proxima centuri to reach the earth

Both independent and dependent clauses

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?

Which stable element is used to determine the age of volcanic rock? a- argon b- carbon-14 c- potassium d- carbon-12