Two brass rods used as compression members, each of 6-ft effective length, have the the same cross sections.Theround rod has an outer diameter of 3 inches and an inner diameter of2 inches. The square rod has an outer diameter of 3 inches. (a) Determine the wall thickness of the hollow square rod for which the rods have the same cross-sectional area. (b) Using E = 15 x 10^6 psi, determine the critical buckling load of each rod.