A spring exhibits a force-versus-displacement characteristic as shown in Figure E2.11. For small deviations from the operating point xo, find the spring constant when xo is

(a) −1.1,

(b) 0, and

(c) 2.8.

Spring force (N) 40 30 20 10 0 0 -10 10 -20 -30 -40 -2 -1 1 2 3 4 x, deflection (cm) FIGURE E2.11 Spring characteristic.