Question

A stress ${10}^7$ Pa produces a strain of 4 x 10${}^{-3}$. The energy stored per unit volume of the body (in J.m${}^{-3}$) is

• A. 2 x 10${}^3$
• B. 2 x 10${}^4$
• C. 2.5 x 10${}^{10}$
• D. 0.8 x 10${}^4$

Answer 1

Answer: (B)

2 x 10${}^4$

$energy=\frac{1}{2}\times stress\times strain\times volume$

$\frac{energy}{volume}=\frac{1}{2}\times stress\times strain$

$=\frac{1}{2}\times {10}^7\times 4\times {10}^{-3}$

$=2\times {10}^{4}J/m^3$