Acompound tube is made by shrinking one steel tube onto another. the dimensions of the assembly are 152 mm internal diameter, 305 mm at the common interface and 355 mm external diameter. a strain gauge mounted in a circumferential direction on the outer surface of the assembly records a strain ε0=770μ after the shrinkage of the outer tube onto the inner tube. determine: a) the interfacial pressure at the common interface. b) the initial interference between the two tubes. c) the maximum circumferential stress. take young's modulus e =207 gpa