Work done is area under force-extension graph

Steps:

• Note initial force is 50 N; extension increase Δx = 2 mm = 0.002 m.
• From graph, force at +2 mm extension is 110 N (straight line segment).
• Area = trapezoid = average force × Δx = (50 N + 110 N)/2 × 0.002 m.
• Calculate: 80 N × 0.002 m = 0.16 J.

Why C is correct:

• Work-energy principle: work done stretching wire equals area under F-x curve, yielding 0.16 J.

Why the others are wrong:

• A: Underestimates average force (e.g., uses 20 N instead of 80 N).
• B: Possible misread of graph forces (e.g., averages 50 N and 70 N).
• D: Overestimates (e.g., uses constant 125 N force).

Final answer: C