A8-in.-diameter steel shaft is to have a press fit with a 16-in-diameter cast iron hub. both the hub and the shaft are 10 in long. using maximum normal stress theorem and appropriate safety factor, it was identified that the maximum allowable circumferential (a. k.a. hoop or tangential) stress in the hub is to be 7.5 ksi. the moduli of elasticity are 30 x 106 psi for steel and 15 x 106 psi for cast iron. the poisson's ratio for both steel and cast ron is 0.3 and coefficient friction for the two materials is 0.12. determine a. the interference or the original mismatch, 8 b. the maximum axial force required to press the hub on the shaft