/sci/ - Science & Math

Need help with a Hooke's Law problem.

Pedro Martinez is standing on the planet Baseball (r = 5000 km, m = 7.0 x 10^24 kg) with his favorite spring (k = 100 N/m) in his hand. If he puts a 1.2 kg mass on the end of the spring, how far does it stretch? If he then slowly removes 0.3 kg, how far up does the remaining mass move? What mass would be required to stretch the spring 0.35 m?