1.1. The force–extension graphs for four different springs (A, B, C and D) are shown below.

Explain which of the springs (A, B, C or D) has the largest spring constant?

1.2. Explain why the line for spring B has a different shape from the other lines.

1.3. i) A spring has a spring constant of 27 N/m.

The spring is stretched to an extension of 25 cm.

The energy transferred can be calculated using the formula:

energy transferred = 0.5 × spring constant × extension²

Calculate the energy transferred in stretching.

Answer .......................... J [2]

ii) A student set up the apparatus shown in Fig. 20.1.

Fig. 20.1

The students want to plot a force-extension graph for this spring.

Describe how they could use this apparatus to collect data so that the graph could be plotted.

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iii) The spring in Fig. 20.1 has a spring constant of 30 N/m.

This is replaced by a spring with a spring constant of 10 N/m.

What changes should the student make to this method to investigate this spring?

[2]