Serway & Jewett — Static Equilibrium and Elasticity: Problem 38

Figure P12.38 shows a light truss formed from three struts lying in a plane and joined by three smooth hinge pins at their ends. The truss supports a downward force of \( \vec{F} = 1000 \text{ N} \) applied at the point B. The truss has negligible weight. The piers at A and C are smooth. (a) Given \( \theta_1 = 30.0^\circ \) and \( \theta_2 = 45.0^\circ \), find \( n_A \) and \( n_C \). (b) One can show that the force any strut exerts on a pin must be directed along the length of the strut as a force of tension or compression. Use that fact to identify the directions of the forces that the struts exert on the pins joining them. Find the force of tension or of compression in each of the three bars.