Q4) The rigid platform in Fig. 4 has negligible mass and rests on two steel bars, each 250.00 mm long. The center bar is aluminum and 249.90 mm long. Compute the stress in the aluminum bar after the center load P = 400 kN has been applied. For each steel bar, the area is 1200 mm² and E, = 200 GPa. For the aluminum bar, the area is 2400 mm² and EAI = 70 GPa. Steel Aluminum Steel Figure 4