Question

One end of a 50 cm length of wire is attached to a support. A load is attached to the free end of the wire, which extends by 2 mm.

Which of the following is the strain for the length of wire?

A 0.004

B 0.04

C 25

D 250

Answer 1

By definition, the strain is:

$$\epsilon = \dfrac{\Delta L}{L}$$

where $\Delta L = 2mm = 0.2cm$ is the extension, and $L = 50cm$ is the initial length of the wire. Thus, obtain:

$$\epsilon = \dfrac{0.2cm}{50cm} = 0.004$$

Answer. 0.004.