The graph indicates how the spring’s length changes with the force exerted on it. The spring has unstretched length $L_0$. If a force $F$ is applied, the spring then has length $L_1$. What is the work done in extending the spring to length $L_1$?
- A$\frac{1}{2} F L_1$
- B$\frac{1}{2} F (L_1 - L_0)$
- C$F L_1$
- D$F (L_1 - L_0)$