When a 2.50 - kg object is hung vertically on a certain light spring described by Hooke’s law, the spring stretches 2.76 cm. (a) What is the force constant of the spring? (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? (c) How much work must an external agent do to stretch the same spring 8.00 cm from its unstretched position?
