Learning Goal: To apply the method of sections to find the forces in specific members of a truss. The method of sections is used to find the force in a specific member of a truss and is based on the principle that, if a body is in equilibrium, then every part of that body is also in equilibrium. When applied, the method of sections "cuts" or sections the members of a truss and exposes their internal forces. To find the unknown internal member forces, the free-body diagram of a section is drawn and the equations of equilibrium are applied: ΣΜ0 - 0 Because there are only three independent equilibrium equations, section cuts should be made such that there are not more than three members that have unknown forces. Part A As shown, a truss is loaded by the forces P₁ = 497 lb and P₂ = 198 lb and has the dimension a = 9.40 ft. L. B FBC = ΣF - 0 ΣΕ, = 0 C H a/2 a/2 Determine Fc, the magnitude of the force in member BC, using the method of sections. Assume for your calculations that each member is in tension, and include in your response the sign of each force that you obtain by applying this assumption. 10] ΑΣΦ / 11 /vec ? lbs

Q2/ A) Knowing that A = 2i+mj+k & B-5i +j+4k are perpendicular vectors. Find the %3D value of m then find A x B

2. Find an unit vector perpendicular on both ä =7 +27- and 5 21 -k. 3. Consider the triangle ABC where A(1,3,5), B(-2,1,0), and C(0,1,-1). [2] a) Find the angle ZA. [2] b) Find the area of the triangle ABCD. 4. Find the resultant force of the following system of forces. 2ON 540 (ON V (ON

If line AB and line AC are two sides of the diagram, at which coordinates should point D be placed so that ABDC is a parallelogram? Point D should at(_,_).