Halliday, Resnick & Walker — Kinetic Energy and Work: Problem 27

27 A spring and block are in the arrangement of Fig. 7-10. When the block is pulled out to \(x = +4.0 \text{ cm}\), we must apply a force of magnitude \(360 \text{ N}\) to hold it there. We pull the block to \(x = 11 \text{ cm}\) and then release it. How much work does the spring do on the block as the block moves from \(x_i = +5.0 \text{ cm}\) to (a) \(x = +3.0 \text{ cm}\), (b) \(x = -3.0 \text{ cm}\), (c) \(x = -5.0 \text{ cm}\), and (d) \(x = -9.0 \text{ cm}\)?