The gradient of the line \(\frac{\text{F}}{\text{e}}\) is the spring constant, k. Key fact The gradient of the graph of force F, (y-axis), and extension e, (x-axis), is equal to the spring constant k.

A force-extension graph can be used to calculate the work done in joules when stretching a spring. Force should be plotted on the vertical (y) axis Extension should be plotted on the horizontal (x ...