Learning Goal: Member DH is in compression To apply the method of sections to a truss and determine the unknown forces in specified members. If a truss is in equilibrium then every member in the truss must also be in equilibrium. This principle is used in analyzing a Member GH is in compression truss using the method of sections. To apply the method of sections, we use an imaginary cut through members of the truss to expose the forces in those members as external forces. (Figure 1) f the free-body diagram of the joint on either side of the cut is known, we can apply the equations of equilibrium to that part of the member to determine the forces at the cut section. Since only three equilibrium equations ( F. = 0, _ Fy = 0, and > Mo = 0) can be applied to the free-body diagram of any segment, we should try to select a cut that passes through Submit Previous Answers no more than three members of the truss in which the forces are unknown. Note that the moment equation can be written multiple times, but there are still only 3 independent equilibrium equations available. Correct For the Howe bridge truss shown, d = 11 ft, Fi = 2950 1b, F2 = 1850 lb, F3 = 2650 lb, and F4 = 3950 lb. (Figure 2) Part C - Determining the forces in three members on the left-hand side of the truss Determine the forces in members HI, BH, and BC. Express the magnitudes of the forces in pounds to three significant figures. Separate your answers with commas. View Available Hint(s) AEd It vec FBC =, FHI =, FBH = lb, lb, Ib Submit Previous Answers X Incorrect; Try Again Part D - The Sense of the Forces State if the members considered in part C are in tension or compression. Complete each sentence by dragging the appropriate word into the blank. The words can be used more than once. Reset Help compression Member BC is in tension tension Member HI is in compression Figure Member BH is in compression Submit Previous Answers Correct Provide Feedback