A force-extension graph for a spring is shown - Edexcel - A-Level Physics - Question 8 - 2023 - Paper 2

To calculate the work done on the spring, we can use the area under the force-extension graph.

1. Determine the force at the extension of 0.15 m: From the graph, the force corresponding to an extension of 0.15 m is 2.5 N.

2. Calculate the work done:
   The work done (W) on the spring can be calculated using the formula:
   $W = \frac{1}{2} \times \text{Force} \times \text{Extension}$
   Substituting the values:
   $W = \frac{1}{2} \times 2.5 \times 0.15 = 0.1875 \text{ J}$
   Since the question asked for the method to compute work done, the formula can be rearranged:
   The equivalent expression that fits our answer choice is B, which simplifies as follows:
   $0.5 \times 0.15 \times 2.5 = 0.1875 \text{ J}$
   Therefore, the correct answer is B: 0.5 × 0.15 × 2.5.