Question

Determine the force in each member of the scissors truss shown in Fig. 3-21a. State whether the members are in tension or compression. The reactions at the supports are 175 lb to C given. 200 Ib A;-141.4 lb 60° 45 ES 60 E 30 30° 10 ft -10 ft A, 125.4 lb E - 191.0 lb (a) Fig. 3-21 FED FEF E 15° 30 191.0 lb (b) Foc 75° D FoF 639.1 lb (c) 175 lb FCB 45T 639.1 Ib 45 FcF 639.1 lb (d) 200 lb 75° Fsf FEA (e) 692.7 lb FAF 45e A 141.4 lb 30 125.4 lb (0

Answer 1

Page- Fsee body diagram of foirt E 18 qrenin Lig- Fy o NO > 91 Sin FED 8in(s FED6.1 (tve gign meary Ziven dixedion of force is Corseck, ip foxce towavd joint meag it 1s Compresion, and away from doint meanu tension FE= 639. (o lb Compression FEE t 191Cog (60° = Fr cos(i59) 91 Cas (609 639.j0 cos( ir FeE Fer (tve ign eans given dixecion of Fer Cored, it is away from Joint E so, Tension FE Tension F = S21R2 Gojnt D:- COnsider FPF Sin (150) =0

page-2 towandsoint to (ompfesb 63q.1 Lb Fdc= 62q.1 b Compresion Consider doink C 639. Sin(459) com press ion FCR CosCA +*630.1 os(u -> CF GA.1 Cos(45+ 63q.1 Cas(u9-(15 J28. 8216(ao fom jo'int, Tensioh Con Sider joi n 639.1 200lo FRE 200FRE 9in(u50 L07.055 LbCompresion) 639.1 + Fge Cos(759) FRA SF RA =3Cq.1 287, as oslis 692.69 bComves sio a)

Paga Considen joint 627 >FAF 300 lu1.4 6921 (os( 45) FAr COS (36 Tension)