2–5 Poisson’s ratio n is a material property and is the ratio of the lateral strain and the longitudinal strain for a member in tension. For a homogeneous, isotropic material, the modulus of rigidity G is related to Young’s modulus as G 5 E 2(1 1 n) Using the tabulated values of G and E in Table A–5, calculate Poisson’s ratio for steel, aluminum, beryllium copper, and gray cast iron. Determine the percent difference between the calculated values and the values tabulated in Table A–5. 2–6 A specimen of steel having an initial diameter