Question

If $s$ is the stress & $y$ is youngs modulus of material of wire. What is the energy store in the wire per unit volume. In terms of $s$ & $y$.

Answer 1

We know that energy stored is given as

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

$y=\frac{Stress}{Strain}$

$Strain=\frac{Stress}{y}$

$U=\frac{1}{2}\times \left(stress\right)\times \left(\frac{Stress}{y}\right)$

$U=\frac{1}{2}\times \left(s\right)\times \left(\frac{s}{y}\right)$

$U=\frac{s^2}{2y}$