A steel rod of length $\ell$, cross sectional area $A$, young's modulus of elasticity $Y$, and thermal coefficient of linear expansion $'a'$ is heated so that its temperature increases by $t\,^oC$. Work that can be done by rod on heating will be
$(YA\, \alpha\, t)\times(\ell\, \alpha\, t)$
$\frac{1}{2}\left( {YA\,\alpha \,t} \right) \times \left( {\ell \,\alpha \,t} \right)$
$\frac{1}{2}\left( {YA\,\alpha \,t} \right) \times \left( {1/2} \right)\left( {\ell \,\alpha \,t} \right)$
$2(YA\, \alpha\, t)\,(\ell\, \alpha\, t)$
A stretched rubber has
The work done per unit volume to stretch the length of area of cross-section $2 \,mm ^2$ by $2 \%$ will be ....... $MJ / m ^3$ $\left[Y=8 \times 10^{10} \,N / m ^2\right]$
The work done in stretching an elastic wire per unit volume is
When shearing force is applied on a body, then the elastic potential energy is stored in it. On removing the force, this energy
A uniform wire of length $L$ and radius $r$ is twisted by an angle $\alpha$. If modulus of rigidity of the wire is $\eta$, then the elastic potential energy stored in wire, is .........