A steel wire of length 2 m and Young's modulus 2.0 1011 N m-2 is stretched by a force. If Poisson's 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).
Answer
25
Solution
Poisson's ratio: = transverse strainlongitudinal strain
longitudinal strain = 10-30.2 = 5 10-3
Energy density: u = 12Y(strain)2
= 12 2 1011 (5 10-3)2
= 25 105 J m-3
Answer: 25