Question

A wire 4 m long and 0.3 mm diameter is stretched by a force of 100N. If the extension in the wire is 0.3 mm, calculate the potential energy stored in the wire.

• A. 15J
• B. 25 J
• C. 15 $\times {10}^{-3}$J
• D. 25 $\times {10}^{-3}$ J

Answer 1

The correct option is C

15 $\times {10}^{-3}$J

$U=\frac{1}{2}\left(stress\right)\left(strain\right)\left(volume\right)$

$=\frac{1}{2}\times \left(Force\right)\left(elongation\right)$

$=\frac{1}{2}\times 100\times 3\times {10}^{-4}$

$=15\times {10}^{-3}$J