In a tensile test for an alloy used for ballistic-missile launch tubes on "boomer" submarines the yield strength was determined to be 36,000 psi, based on an of set strain of 0.15%. The modulus of elasticity was found to be E= 15x10^6 psi. find (a) total strain corresponding to yield strength, (b) what portion of the total strain in part 'a' is elastic and (c) what portion is plastic? (d) at a tensile stress of 42,000 psi the total tensile strain was found to be 0.009 in/in. determine the plastic portion of this total strain.