Chapter 12, Problem 57P

(III) The truss shown in Fig. 12–72 supports a railway bridge. Determine the compressive or tension force in each strut if a 53-ton (1 ton = 10³ kg) train locomotive is stopped at the midpoint between the center and one end. Ignore the masses of the rails and truss, and use only $\frac{1}{2}$ the mass of train because there are two trusses (one on each side of the train). Assume all triangles are equilateral. [Hint: See Fig. 12–29.]

FIGURE 12–72

Problem 53.