第一部分靜力學(xué)2/22/20231次數(shù)章節(jié)題目一1(S)P23-1.1(l)(g)、P24-1.2(k)、P27-1.3(c)(e)二2(S)P58-2.3、P60-2.14、P61-2.20三2(S)P63-2.28、P63-2.30、P64-2.32、P64-2.34四3(S)P85-3.2、P86-3.11、P87-3.18、

P90-3.28(f)、P91-3.40、P92-3.43五4(S)P111-4.2、P113-4.12、P113-4.13六4(S)P114-4.14(b)、P115-4.24、P116-4.27七5(S)P131-5.2、P132-5.12、P133-5.18、P133-5.19、P134-5.22作業(yè)題目作業(yè)題目2/22/20232P23-1.1(l):2/22/20233P23-1.1(g):2/22/20234P24-1.2(k):2/22/20235P27-1.3(c):2/22/20236P27-1.3(e):2/22/20237P58-2.3:Solution:由此得到如下方程組：解得：2/22/20238P60-2.14:Solution:按定義有:So,expressions(a),(d),(e)arevalid.2/22/20239P61-2.20:Solution:(a)Vectorform:2/22/202310(b)Vectorform:2/22/202311P63-2.28:++Solution:2/22/202312P63-2.30:++（a)Solution:2/22/202313(b)+2/22/202314OOriginalforcesandcouplecanbereducedtoaforceandacoupleactingatpointO:P64-2.32:Solution:于是得到合力的大小、方向和作用線位置（如圖所示）：(或,或)2/22/202315P64-2.34:+Solution:2/22/202316P85-3.2:Solution:RAyRByFromtheFBDofthebeaminFig:+RBx3kN2m++2/22/202317P86-3.11:Solution:GPGL把人和梯子作為研究對(duì)象，作出FBD(a)x=1.5m+RBRAyRAx+2/22/202318+GPGLRBRAyRAx(b)2/22/202319P87-3.18:Solution:300N0.5mRDRE(1)StudyingentirestructureFromtheFBDofentirestructureinFig:+(2)StudyingmemberABFromtheFBDofmemberABinFig:RBxRByRAxRAy300N0.5m1.6m+2/22/202320(3)StudyingmemberACEFromtheFBDofmemberACEinFig:0.8mRERAxRAyAECRCxRCy0.8m0.6m0.6m+++2/22/202321P90-3.28(f):Solution:(1)StudyingmemberCDFromtheFBDofmemberCDinFig:顯然，本題中在約束A、B、C、D處沒有水平方向的作用力RCRＤMRCRＤ2qCＤ3m1m++2/22/202322(2)StudyingmemberABCRARCRB2qAC1m2mＢRARCRB1mFromtheFBDofmemberCDinFig:++2/22/202323P91-3.40:Solution:(1)FromtheFBDofjointAinFig:APFABFAD12++2/22/202324(2)FromtheFBDofjointBinFig:BPFBCFBDFAB++2/22/202325(3)FromtheFBDofjointDinFig:DFBD++FDEFADFCD1212122/22/202326(4)FromtheFBDofjointCinFig:CRCFCEFBCFCD12+2/22/202327P92-3.43:Solution:(1)FromtheFBDofjointDinFig:DPFCDFDH+(1)FromtheFBDofjointＨinFig:HFDHFGＨFCＨ2323++2/22/202328P111-4.2:Solution:+++++2/22/202329P113-4.12:Solution:RAzRAyRByRBxRCxRCzFromtheFBDofbentpipeandcableinFig:2/22/202330無(wú)解！？2/22/202331P113-4.13:Solution:2/22/202332P114-4.14(b):Solution:S令形心坐標(biāo)為(xc,yc),按定義有:2/22/202333P115-4.24:Solution:已知crucible的密度rc=2000kg/m3,外徑R=0.28m,內(nèi)徑r=0.2m;iron的密度ri=7200kg/m3OStudyingcrucible，DrawingFBDinFig.WiWcGiGcFyFx+2/22/202334OWiWcGiGcFyFx2/22/202335P116-4.27:Solution:x=0

2/22/202336xyO2xyO1P131-5.2:解：30°36lb20lb18in假設(shè)系統(tǒng)是靜力平衡的先研究圓柱，有P1G1G2N1N2f2f1P1得再研究方塊，有得而因，所以系統(tǒng)不能保持靜力平衡2/22/202337P132-5.10:Solution:總體分析:

分析木條:圓盤分析:解之得：

NfffCBA.=22.06==達(dá)到最大靜摩擦力時(shí):解之得：

2/22/2023389000N/mBCDBCDP132-5.12:解：P假設(shè)系統(tǒng)是靜力平衡的先研究樁子CBD，有NBNBNAfAfBRxRy再研究桿AB，有P9000N/m1.5m2m3m0.8mABCDABfBAB2/22/202339只有當(dāng)fA>fAmax或fB>fBmax時(shí)，桿AB才能移動(dòng)，由以上計(jì)算結(jié)果可知，當(dāng)P>6300(N)，桿AB在