2.1.7 Calculating Truss Forces Upd -

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.

Joint A (left bottom): Forces: AB (to right), AC (up-right, 45°), reaction 5 kN up. ΣFy = 0: AC·sin45° + 5 = 0 → AC = –7.07 kN (compression). ΣFx = 0: AB + AC·cos45° = 0 → AB = 5 kN (tension). 2.1.7 calculating truss forces