An $8\,m$ long copper wire and $4\,m$ long steel wire, each of cross section $0.5\,cm^2$ are fastened end to end and stretched by $500\,N$ force. The elastic potential energy of the system is (Youngs mod $: Y_{cu}= 1\times 10^{11}\,N/m^2,$ $Y_{steel} = 2\times 10^{11}\,N/m^2$ ) :
A solid expands upon heating because
The strain energy stored in a body of volume $V$ due to shear strain $\phi$ is (shear modulus is $\eta$ )
When load of $5\,kg$ is hung on a wire then extension of $3\,m$ takes place, then work done will be ....... $joule$
A stretched rubber has