Notes and examples in mechanics; with an appendix on the graphical statics of mechanism; (1897)
Church, Irving P. (Irving Porter), 1851-1931 · New York, J. Wiley & Sons · leaf 43
to furnish allthe horizontal resistance. Hencethe system of forces acting on thewhole truss, considered free, willbe as shown in Fig. 36, in whichthere are three unknown reac-tions (or pressures, of the support-ing surfaces), F„, y„,and^. IIbecomes known from ^X =: 0^ viz., 2W^maBy moments about… … Fig. 36. 11=0. (1) SIMPLE ROOF-TllUSS. 35 [Note.—HaviDg now made use of three independent equations,based on the laws of equilibriinn of forces, and by their aid de-termined three quantities originally unknown, the student shouldnot imagine that by putting ^ Y =: 0, or by writing anothermoment…
