Before starting any calculations, engineers simplify the real-world complexity of a truss using three standard assumptions: All members are joined together by smooth pins. All loads and reactions are applied at the joints.
Pass an imaginary "cut" through the truss, slicing through the members you want to solve. 2.1.7 calculating truss forces
ΣM(left pin) = 0 → Right reaction × 6 m – 10 kN × 3 m = 0 → Right = 5 kN ↑ ΣFy = 0 → Left reaction = 5 kN ↑ ΣFx = 0 → Left horizontal = 0. Before starting any calculations