QUESTION #4 Trusses 3 m. BY 3 m 5 kN 4 kN 3 m 3 m Figure 3 5 m [21 marks] As shown in Figure 3, a truss is pinned to a vertical wall D and rolls on a horizontal surface at E. (a) Determine the reactions at the truss's supports. [4 marks] (b) Use method of joints to determine the forces in members BC, FC and AE. State whether or not these members are in tension or compression. [9 marks] (c) Use method of sections to determine the forces in members BC, FC and AE, i.e. confirm the answers arrived at in Part (b). [8 marks] QUESTION #5 Internal Forces 150 lb/ft page 3 of 7 C -10 ft Figure 4 2 ft 2 ft E D [21 marks] As shown in Figure 4, a compound bean comprises a weightless beam CD that supports another beam AE at roller B. Beam AE weighs 150 lb/ft. (a) Determine the reaction at the supports of AE. (b) Determine the reaction at the supports of CD. [4 marks] [4 marks] (c) Determine the shear and bending-moments at the midpoint of each beam segment. [6 marks] (d) Draw the shear and bending-moment diagrams for each of the two segments of the compound beam. State the values at relevant locations along the diagrams. [7 marks] QUESTION #6 Centroids and Moments of Inertia 3 cm 3 cm 5 cm 1 cm 1 cm [21 marks] Figure 5 Figure 5 shows the shape of a piece of sheet metal. The material has a thickness of 1 mm and a density of 7800 kg/m. (a) Determine the area of the sheet metal, i.e. the area of the shaded region in Figure 5. [4 marks] (b) Determine the mass of the sheet metal. [4 marks] (c) Determine x,y, i.e. the location of the centroid the sheet metal. [6 marks] (d) Determine the moment of inertia of this area about the axis parallel to the x-axis and passes through the centroid. [7 marks]