Q.

A steel wire of length 2 m and Young's modulus 2.0×1011Nm–2 is stretched by a force. If Poisson ratio and transverse strain for the wire are 0.2 and 10–3 respectively, then the elastic potential energy density of the wire is _____ ×105 (in SI units)          [2025]


Ans.

(25)

U=12×Y×(longitudinal strain)2

σ=|transverse strainlongitudinal strain|

Longitudinal strain = 10–30.2=5×10–3

U=12×2×1011×25×10–6

      =25×105 J/m3