3. As shown in figure, there is a gap between the aluminum bar and the rigid slab that is supported by two copper bars. At 10°C, the gap between aluminium bar and rigid slab is A = 0.18 mm. Neglecting the mass of the slab, calculate the stress in each rod when the temperature in the assembly is increased to 95°C. For each copper bar, A = 500 mm², E=120 GPa, and a = 16.8 x 106/°C. For the aluminum bar, A =400 mm², E = 70 GPa, 23.1 x 106/°C. and a = Copper Aluminum Copper 750 mm