A10.1 g bullet leaves the muzzle of a rifle with a speed of 425 m/s. what constant force is exerted on the bullet while it is traveling down the 0.6 m length of the barrel of the rifle?

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?