理论力学(第七版)课后题答案解析哈工大.pdf

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1、第1章静力学公理和物体的受力分析1-1画出下列各图中物体A，ABC或构件AB，AC的受力图。未画重力的各物体的自重不计，所有接触处均为光滑接触。FN1APFN2(a)(a1)FTAPFN(b)(b1)AFN1PBFN3F开网店找财富QQ764123858N2(c)(c1)FTBFAyP1PA2FAx(d)(d1)FFABFAB(e)(e1)1qFFFAyBFAxAB(f)(f1)FBCFCAFA(g)(g1)FAyFCCAFBAxP1P2(h)(h1)BFCF开网店找财富QQ764123858CFAxDAFAy(i)(

2、i1)(j)(j1)BFFBCPFAyFAxA(k)(k1)2FCAFABF′ACCAF′ABBFACFABAP(l)(l1)(l2)(l3)图1-11-2画出下列每个标注字符的物体的受力图。题图中未画重力的各物体的自重不计，所有接触处均为光滑接触。CFN2FN′P2(a)(a1)BFN1FBN1CFN2FNP2P1P1FAyFAy开网店找财富QQ764123858FAxFAxAA(a2)(a3)FN1AP1FBN3P2FN2(b)(b1)F′NFABN3FN1P2P1FFNN2(b2)(b3)3FAyFAAxCDFN

3、2BP2P1FN1(c)(c1)FAyFTFAAxDF′FTN2BP1FPN12(c2)(c3)FAyFqBAFCDBAxFC(d)(d1)FAyFDyqFB开网店找财富QQ764123858qDF′BAFCFDDxAxDxFCFDy′(d2)(d3)FAyqFBx′BFFAyAxqABF′FByAxFCyFFCxCPABBxPCFCxFByFCy(e)(e1)(e2)(e3)F1CFF2AyFByABFFAxBx(f)(f1)4FCxCFCx′CF1FAyFCyFCy′F2FByAFBxFAxB(f2)(f3)FFB

4、AyCBAFAxP(g)(g1)F′CyFTF′CCxFAyFBFTFDCAxBAFCxP(g2)(g3)DF1FCyFBF′F开网店找财富QQ764123858B2BCFCxBFAyAFAx(h)(h1)(h2)AFAxFAyFCyFCxCF′AFCyEFFOyCDFOxFCx′EOB(i)(i1)(i2)5AAF′AxF′F′EAyFECDFFByFByOyFBxOFOxFBxBB(i3)(i4)FAyDEFACxCFAxCFTFByHFByFCyBPFBxBFBx(j)(j1)(j2)FAyFDy′FEy′FT′

5、2EFCFCx′DFT2AxF′ExFFExADFDx′EDxFFT3T1FFF′DyEyCy(j3)(j4)(j5)开网店找财富QQ764123858EFFBCEDF′BCxθF′F′CyDE(k)(k1)FFBFCBFECxθCFCy90°−θFDEDDFAyFAyAFAFAxAx(k2)(k3)6FBFF′1BFBDBDACFFAC(l)(l1)(l2)F2F′DDF1F2DBACEEFEFAFCFE(l3)(l4)或F′FFFB′FDy2F1F1Dy2F′DDxBDFDxDBFExACFCEEExFCFEyFA

6、FCFEy开网店找财富QQ764123858(l2)’(l3)’(l4)’F′ADAFCyFCxCF1B(m)(m1)FADDFADEHF2ADFFF′EHAD(m2)(m3)7FANAFkFNBFOyFOxBO(n)(n1)FN1BDqF′BFN2FN3(n2)FBDFFFCFEAGFACEG(o)(o1)FBBDFDFBFFCFDEF开网店找财富QQ764123858AFAFB′CFD′EF(o2)(o3)(o4)图1-28第2章平面汇交力系与平面力偶系2-1铆接薄板在孔心A，B和C处受3个力作用，如图2-1a所示

7、。F=100N，沿铅1直方向；F=50N，沿水平方向，并通过点A；F=50N，力的作用线也通过点A，尺32寸如图。求此力系的合力。yFc3dF2F1F2bFFAF3x1R60θa(a)(b)(c)图2-1解（1）几何法作力多边形abcd，其封闭边ad即确定了合力FR的大小和方向。由图2-1b，得22F=(F+F×4/5)+(F+F×3/5)R123222=(100N+50N×4/5)+(50N+50N×3/5)=161NF+F×4/512∠(F,F)=arccos()R1FR100N+50N×4/5oo=arccos(

8、)=29.74=2944′161N（2）解析法建立如图2-1c所示的直角坐标系Axy。∑F=F+F×3/5==50N+50N×3/5=80Nx12∑F=F+F×4/5=100N+50N×4/5=140N开网店找财富QQ764123858y12F=(80i+140j)NR22F=(80N)+(140N)=161NR2-2如图2-2a