The bronze bar 3 m long with a cross-sectional area of 350 mm is placed between two rigid walls. At a temperature of -20C, there is a gap A = 2.2 mm, as shown in the figure. Find the temperature at which the compressive stress in the bar will be 30 MPa. Use x = 18.0 x 10-6/C and E= 80 GPa. 3 m- FIG. P2.78 HAK