1.5 PROBLEMS REVIEW OF EQUILIBRIUM; DETERMINATION OF INTERNAL RESULTANTS Problems 1.4-1 through 1.4-6. In these truss equilib- rium problems, adopt the sign convention for axial force that a tensile force is positive. That is, on your free-body diagrams, show all unknown forces F, as tensile forces. Then, a force that is compressive will be negative. Prob. 1.4-1. The pin-jointed truss in Fig. P1.4-1 supports a load of P-2 kips at joint C. Determine the axial forces F through Fs in the truss members. determine the axial force in each of the following mem- bers: F₁ (in member AB), F, (in member BC), and F, (in member CD). (1) 0.6 m (2) (3) I KN 0.7 m 0.4 m (1) (3) (2) 6ft (4) (5) D C 8 ft. 6ft P1.4-1 and P2.2-12 Prob. 1.4-2. Each member in the pin-jointed planar truss in Fig. P1.4-2 is 6 ft long. The truss is attached to a firm base by a frictionless pin at A. and it rests on a roller support at B. For the loading shown, (a) determine the reactions at A and B, and (b) determine the force in each of the three members labeled (1) through (3). (3) 3 kips 0.6 m 1.2m P1.4-3 Prob. 1.4-4. For the pin-jointed truss in Fig. P1.4-4. (a) deter- mine the reactions at the supports at A and C; and (b) deter- mine the axial force in each of the following members: F, (in member AB), F, (in member BC), and F, (in member CD). Express all of your answers in terms of the weight W. Note: CD and DE are two separate members that are pinned to member BD at D. (1) 10 ft (2) 10 ft (3) D W (1) 76 kips P1.4-2 Prob. 1.4-3. For the pin-jointed truss in Fig. P1.4-3. (a) de- termine the reactions at the supports at A and C, and (b) 8 ft 8A- 8 ft- P1.4-4 Prob. 1.4-5. The pin-jointed truss in Fig. P1.4-5 supports equal vertical loads P at joints B, C, and D. (a) Determine the reactions at the supports A and E, and (b) use the method of sections to determine the forces in the following 17