Question

1. Determine the force in all members of the truss using the method of joints 2. Determine the force in members DE,DB and AB using the method of sections To begin the analyse linear unknown forces a of the joints in Figure criteria. Therefore, we equations applied to the © = 0 M = 0 - 10 OXF, = 0 OK B 10 kip to 3 ft to 3 ft + 3 ft 3 ft . (a)

Answer 1

(1) The given figure is Bllokip " 34 34 ! & 346 347 3K e 10 Kip Y all members we have to determine the force in all using method of joints The viteria's included arg {Fx=0, EMATO {fy to For Efyzo VAT V = 10 kip EMA=0 (V x 12) = 10x 6 = skip As per the geometry VA = V = 5kup Let us find the force at Joint A - o can be obtained as Tano = 4/ 0 - 53.13° Ав for Efyzo - VA = FAD sine. FAD = I. - 5313 FAO = 6.25 kip for Efnzo - FAB = FAD (Loso) FAB = 6.25 x (cos (53:13) FAB = 3.75 kip

forces are equal Due to similar and equal geometry FAB = Fbc = 3.7 kip FAD = FEC = 6.25 kip Fво - тве Let us find force at Joint Bi. {fyzo - (FBD Sin 0 ) x2 = 10 FOD=FBE = 153 157 13 = 6 12 skip 53.13 53.13 2 sir 53.13 Å San 3 At Joint D:- EF M = 0 ) Fadino + Foosino=FOE FOE = (61 25 X sin 36:86) + (6125xsin 36:38) TE = 7.49 kip :. The forces using method of joints FAD = FEc = 6.25 kip, FAB = FBc = 3.7kip , FBD = FBE = 6: 25kup FDE = 7.49 kip (2) we have to determine the forces by usind method of sutions. The section was duided EMATO, moment dies to DB and AB are zero as Ā these are coplanar members .. VAX6=EDEXY FDE = 586 FDE T (VA= skip) FIE = 7.5 kip

We have another condition i es Ely=0 VA = Foo coso = FBox (OS 36.86 FBD = 5 . FBD = 6.25 kup cos 36.86 Emozo FAB = 6: 25 x cos (5 3:13) FAB = 3.75 kip