Hooke's law is applicable to idealized (linear) springs that are not stretched or compressed too far. Consider a nonlinear spring whose restoring force is given by F(x) = 15x - 0.3x3, for |x| ≤ 8. How much work is done in compressing the spring from its equilibrium position (x = 0) to x = -0.5? Round to two decimal places when appropriate.
◦ 3.73 J
◦ 172.8 J
◦ 345.6 J
◦ 1.87 J