When a 4.32 kg object is hung vertically on a certain light spring that obeys Hooke's Law, the spring stretches 2.92 cm.
(a) If the 4.32 kg object is removed, how far will the spring stretch if a 1.50 kg block is hung on it?
(b) How much work must an external agent do to stretch the same spring 4.00 cm from its unstretched position?