Question 1 Report
The graphs in Fig. 1 show force against extension for four springs. Which graph shows a spring that is stretched beyond its limit of proportionality?
The spring stretched beyond its limit of proportionality is the one whose line starts straight and then curves (labelled B in the figure). Up to the limit of proportionality the force-extension graph is a straight line through the origin; past that point extra load produces disproportionately more extension, so the line bends away from the straight part. The fully straight graphs stay within the limit of proportionality, and the flat horizontal graph shows extension with no increase in force, neither of which is the curving-beyond-the-limit behaviour asked for.
Everything you need to excel in your exams