理论力学全套解疑06

6-1Q=420(N)ABACAD6-1(a)AB=1450(mm)AC=800(mm)AD=600(mm)CADEBABACAD6-lA6-1(b)AQABADTCTDABTBABAxyz(1)0cos,0=−−=∑αBTQZ(2)0cossin,0=+=∑βαBCTTX(3)0sinsin,0=+=∑βαBDTTY1000600sin1000800cos14501050sin1cos14501000sin222=====−==+=′=AECEAEACABADACABBAββααα(1)(2)(3)N240N320N580==−=DCBTTABTTBZαcosBBxTT=TBxyTBxyTBxyαsinBBxyTT=TBxyxyβαββαβsinsinsincossincosBBxyByBBxyBxTTTTTT====6-2(a)R′MO6-2R′MOO′mO′(R′)=−MOR′OO′RMO′=mO′(R′)MO′=mO′(R′)=−MO(R′MO)=(RMOMO′)=R6-2(b)(c)ABRAMARBMBRARBMAMBRARAR′∑FF1F2FnABRAMARBMBF1F2Fn=RAMA=RBMB(1)RBMBA6-3RAMA=BBBABRMR×+,((2)126-3MA=MB+RB3AB3RMA⋅R=(MB+ABRB)⋅R=MB⋅RF1F2FnOOOxyzz6-4aOR′MOR′=∑FMO=iiO)(FrFm×∑=∑riFizRzriFiFiFizriFizriFiOxyMO=∑riFiOxyR′MOOR′MOR′MO6-4b6-41R′=0MO0MO2R′0MO=0ROR0MO0RROORMdO=3R=0MO=0R′MOOyzxx0)(0)(0)(00=====∑∑∑∑∑FFFzyxmmmZYyYAYB6-6(a)ABND=20kNPt=117kNPr=36kNPa=22.5kNd=98mmr=440mmmmAB6-66-6(b)02,0)(=−=∑FrdPmtyF(1)132==tPrdFkN(2)0,0=−+=∑aBAPYYY03009009802,0)(=×−×+×−=∑OBraxNZPdPmF(3)ZB=44.6kN(4)0,0=−++=∑rDBAPNZZZZA=−28.6kN0980900300,0)(=×−×−×=∑tBzPXFmF(5)XB=−123kN(6)0,0=+++=∑tBAPFXXXXA=−7kNXA=−7kNXB=−123kNZA=−28.6kNZB=44.6kNF=13kNaBAPYY=+YAYBBBYBYBXAYAZAXBYBZBFFABXAYAZAXBYBZBYAYByyy6-7ABCD6-7aAADP6-7bAxyz10Y∑=4202PS−=42SP=()0ymF∑=34202SaSa−−=i3SP=−()0zmF∑=2422022SaSa+=22SP=−()0xmF∑=123422022SaSaSaSa−−−−=1SP=0X∑=2522022SS−−=52SP=0Z∑=1562452220222SSSSSS−−−−−−=6SP=−20)(=∑FCGm5202PaSa−=52SP=0)(=∑FDHm5422022SaSa−+=42SP=0)(=∑Fym13SP=−0)(=∑Fzm122SP=−0)(=∑FCDm65202SaSa+=6SP=−0)(=∑Fxm11SP=