A cooper tube 55 mm in outside diameter and of will thickness 5 mm fits loosely over a solid steel circular bar 40 mm in diameter. The two members are fastened together by two metal pins each 8 mm in diameter and passing transversely through both members, one pin being near each and of the assembly. At room temperature the assembly is just stress free when the pins are in position. The temperature of the entire assembly is then raised 40°C. Calculate the average shear stress in the pins. For cooper E=90GPa, a=18x10¯6/°C;for steel E=200GPa, a=12x10¯6/°C.