Answer to Question #164208 in Physics for Muhsin

Question

A bar with a square cross section with dimension 14 mm x 14 mm has a force P = 15 kN applied to it axially. The length L of the bar is 497 mm and has a Young’s modulus of 94 GPa. Calculate the extension of the bar due to the axial load applied. Express your answer in mm.

Answer 1

Find the stress:

$$\sigma=\frac FA.$$

Express the strain in terms of stress and Young's modulus:

$$\epsilon=\frac{\sigma}{E}=\frac{F}{AE}.$$

Find the extension:

$$\Delta L=L\epsilon=\frac{FL}{AE}=0.4\text{ mm}.$$