The homogeneous bar with a cross-sectional area of 600 mm is attached to rigid supports. The bar carries the axial loads P = 20 kN and P = 60 kN, as shown. Determine the stress in segment BC. (Hint: Use the results of Prob. 2.55 to compute the reactions caused by P and P acting separately. Then use superposition to compute the reactions when both loads are applied.) A -0.60 m B P 1.20 m P -0.90 m D