Three bars each made of different materials are connected together and placed between two walls when the temperature is 12°C. When the temperature is increased to 18°C, what is the total change in length of the three bars? Properties and dimensions are given in the figure. Answer should be in units of mm. Steel Brass Copper Est = 200 GPa Ebr = 100 GPa Ecu = 120 GPa ast = 12(10-6)/°C abr 21(10-6)/°C acu = 17(10-6)/°C Acu = 515 mm² Ast 200 mm² Abr = 450 mm² -200 mm 300 mm- 100 mm