Physics (AS & A Level) · May / June 2018 · Paper 11 · Question 18

The diagram shows a wire of diameter D and length L that is firmly clamped at one end between two blocks of wood. A load is applied to the wire which extends its length by x. [diagram: blocks of wood, wire, load] A second wire is made of the same material, but of diameter 2D and length 3L. Both wires obey Hooke's law. What is the extension of the second wire when the same load is applied?

1. A\frac{2}{3}x
2. B\frac{3}{4}x
3. C\frac{4}{3}x
4. D\frac{3}{2}x

As printed in the paper