Andre the giant and thumbelina are standing in the middle of an ice-skating rink facing each other. andre the giant pushes thumbelina and she goes sliding, but andre also slides a bit backwards. why did this happen?

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?