When a 2.10-kg object is hungvertically on a certain light spring described by Hooke's law, the spring stretches 2.84 cm.
a) What is the force constant of the spring?
b) If the 2.10-kg object is removed,how far will the spring stretch if a 1.05-kg block is hung on it?
c) How much work must an external agent do to stretch the same spring 8.20 cm from its unstretched position?