A steel beam AD with a 4 cm by 6 cm rectangular cross-section (see left side of the figure below) is simply-supported at sections B and D as shown in the figure. A mass M = 25.5 kg is suspended from a steel rope at section A (gravity is vertically downward) and a constant vertically downward force F = 750 N is applied at section C. a) Draw the free body diagram, shear force diagram, and bending moment diagram for the beam. Include the important numerical values, such as, the reaction forces at the simple supports B and D, the maximum and minimum shear forces, and the maximum and minimum bending moments. b) Locate the critical section of the beam and the critical element at the critical section. Draw the critical element showing the state of stress on this element. c) Determine the maximum normal stress, the minimum normal stress, and the maximum shear stress acting on the critical element of the beam. g = 9.81m/s YA F= 750 N 6 cm A. B D 4 cm 0.5 m 1.5 m 1 m M