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QUESTION 1 (25 marks) External forces are applied to a pin-jointed truss, supported by frictionless rollers at A and hinged at C, as shown in Figure 1. Determine, stating whether the members are in tension or compression: F 18 KN New с 2 m 2 m (a) the forces in members DE, DG and AG, using the Method of Sections, with the aid of free-body diagram of the relevant section, (12 marks) Figure 1 (b) the roller reaction at A, with the aid of free-body diagram of the entire truss, and (4 marks) (c) the forces in members AD and AB, using the Method of Joints, with the aid of free-body of the relevant joint. diagram (8 marks) (d) Identify a zero-force member without any calculation. (1 mark) Ans: 34.86 kN (T), - 40.18 kN (C), - 31.18 kN (C), 23.63 kN, 16.88 kN (T). - 15.097 kN (C), BD 1 m 1 m 5 KN B E G A 60⁰ 2 m LL