Solve the all parts of following question:
Question: When a 2.50-kg object is hung vertically on a certain light spring descrbied by Hooke's law, the spring stretches 2.76 cm.
Part A: What is the force constant of the spring?
Part B: If the 2.50-kg object is removed, how far will the spring stretch if a 1.25-kg block is hung on it?
Part C: How much work must an external agent do to stretch the same spring 8.00 cm from its unstreched position?
Please show all work and steps I am really trying to learn this for my test.