Question

The work done per unit volume to stretch the length of area of cross- section 2 $m{m}^2$ by 2% will be

• A. 40 ${MJ/m}^2$
• B. 16 ${MJ/m}^2$
• C. 64 ${MJ/m}^2$
• D. 32 ${MJ/m}^2$

Answer 1

Answer: (B)

16 ${MJ/m}^2$

We know that

$W=\frac{1}{2}\times Y\times Volume\times {\left(strain\right)}^2$

$\frac{W}{V}=\frac{1}{2}\times Y\times {\left(strain\right)}^2$

Substitute all value in above equation

$\frac{W}{V}=\frac{1}{2}\times 8\times {10}^{10}\times {\left(\frac{2}{100}\right)}^2$

$W=16\times {10}^{6}J$

Correct option is B