Physics (AS & A Level) · Oct / Nov 2017 · Paper 13 · Question 20

A sample of metal is subjected to a force which increases to a maximum value and then decreases back to zero. A force-extension graph for the sample is shown. [graph: force against extension, with points X and Y marked] When the sample contracts, it follows the same force-extension curve as when it was being stretched. What is the behaviour of the metal between X and Y?

1. Aboth elastic and plastic
2. Bnot elastic and not plastic
3. Cplastic but not elastic
4. Delastic but not plastic

As printed in the paper