Determine the values of the stress in portions AC and CB of the steel bar shown Fig. when the temperature of the bar is -45C knowing that a close fit exists at both of the rigid supports when the temperature is +24C. Use the values E = 200 GPa and a = 11.7 x 10-6/C for steel. A = 750 mm A = 380 mm B -300 mm-300 mm-