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1、工程力学吉林大学经典课件Stillwatersrundeep.流静水深流静水深,人静心深人静心深Wherethereislife,thereishope。有生命必有希望。有生命必有希望次数次数 章节章节题目题目一一1(S)P23-1.1(l)(g)、P24-1.2(k)、P27-1.3(c)(e)二二2(S)P58-2.3、P60-2.14、P61-2.20三三2(S) P63-2.28 、 P63-2.30 、 P64-2.32 、P64-2.34四四3(S)P85-3.2、P86-3.11 、 P87-3.18、P90-3.28(f)、P91-3.40、P92-3.43五五4(S)P111
2、-4.2 、P113-4.12、 P113-4.13 六六4(S)P114-4.14(b)、P115-4.24 、P116-4.27七七5(S)P131-5.2、P132-5.12 、P133-5.18 、 P133-5.19 、 P134-5.22作业题目作业题目作业题目作业题目7/21/2024Statics-Problems-2KylinsoftKylinsoftP23-1.1(l):7/21/2024Statics-Problems-3KylinsoftKylinsoftP23-1.1(g):7/21/2024Statics-Problems-4KylinsoftKylinsoftP2
3、4-1.2(k):7/21/2024Statics-Problems-5KylinsoftKylinsoftP27-1.3(c):7/21/2024Statics-Problems-6KylinsoftKylinsoftP27-1.3(e):7/21/2024Statics-Problems-7KylinsoftKylinsoftP58-2.3:Solution:由此得到如下方程组:解得:7/21/2024Statics-Problems-8KylinsoftKylinsoftP60-2.14:Solution:按定义有:So, expressions (a), (d), (e) are va
4、lid.7/21/2024Statics-Problems-9KylinsoftKylinsoftP61-2.20:Solution:(a)Vector form:7/21/2024Statics-Problems-10KylinsoftKylinsoft(b)Vector form:7/21/2024Statics-Problems-11KylinsoftKylinsoftP63-2.28:+Solution:7/21/2024Statics-Problems-12KylinsoftKylinsoftP63 -2.30:+(a)Solution:7/21/2024Statics-Proble
5、ms-13KylinsoftKylinsoft(b)+7/21/2024Statics-Problems-14KylinsoftKylinsoftOOriginal forces and couple can be reduced to a force and a couple acting at point O:P64-2.32:Solution:于是得到合力的大小、方向和作用线位置(如图所示):(或,或)7/21/2024Statics-Problems-15KylinsoftKylinsoftP64-2.34:+Solution:7/21/2024Statics-Problems-16K
6、ylinsoftKylinsoftP85-3.2:Solution:RAyRByFrom the FBD of the beam in Fig:+RBx3kN2m+7/21/2024Statics-Problems-17KylinsoftKylinsoftP86-3.11:Solution:GPGL把人和梯子作为研究对象,作出FBD(a) x=1.5m+RBRAyRAx+7/21/2024Statics-Problems-18KylinsoftKylinsoft+GPGLRBRAyRAx(b) 7/21/2024Statics-Problems-19KylinsoftKylinsoftP87-
7、3.18:Solution:300N0.5mRDRE(1) Studying entire structureFrom the FBD of entire structure in Fig:+(2) Studying member ABFrom the FBD of member AB in Fig:RBxRByRAxRAy300N0.5m1.6m+7/21/2024Statics-Problems-20KylinsoftKylinsoft(3) Studying member ACEFrom the FBD of member ACE in Fig:0.8mRERAxRAyAECRCxRCy
8、0.8m0.6m0.6m+7/21/2024Statics-Problems-21KylinsoftKylinsoftP90-3.28(f):Solution:(1) Studying member CDFrom the FBD of member CD in Fig:显然,本题中在约束A、B、C、D处没有水平方向的作用力RCRMRCR2qC3m1m+7/21/2024Statics-Problems-22KylinsoftKylinsoft(2) Studying member ABCRARCRB2qAC1m2mRARCRB1mFrom the FBD of member CD in Fig
9、:+7/21/2024Statics-Problems-23KylinsoftKylinsoftP91-3.40:Solution:(1) From the FBD of joint A in Fig:APFABFAD12+7/21/2024Statics-Problems-24KylinsoftKylinsoft(2) From the FBD of joint B in Fig:BPFBCFBDFAB+7/21/2024Statics-Problems-25KylinsoftKylinsoft(3) From the FBD of joint D in Fig:DFBD+FDEFADFCD
10、1212127/21/2024Statics-Problems-26KylinsoftKylinsoft(4) From the FBD of joint C in Fig:CRCFCEFBCFCD12+7/21/2024Statics-Problems-27KylinsoftKylinsoftP92-3.43:Solution:(1) From the FBD of joint D in Fig:DPFCDFDH+(1) From the FBD of joint in Fig:HFDHFGFC2323+7/21/2024Statics-Problems-28KylinsoftKylinso
11、ftP111-4. 2:Solution:+7/21/2024Statics-Problems-29KylinsoftKylinsoftP113-4.12:Solution:RAzRAyRByRBxRCxRCzFrom the FBD of bent pipe and cable in Fig:7/21/2024Statics-Problems-30KylinsoftKylinsoft无解!?7/21/2024Statics-Problems-31KylinsoftKylinsoftP113-4.13:Solution:7/21/2024Statics-Problems-32Kylinsoft
12、KylinsoftP114-4.14(b):Solution:S令形心坐标为(xc, yc), 按定义有:7/21/2024Statics-Problems-33KylinsoftKylinsoftP115-4.24:Solution:已知crucible的密度rc=2000kg/m3, 外径R=0.28m, 内径r=0.2m; iron的密度ri=7200kg/m3OStudying crucible,Drawing FBD in Fig.WiWcGiGcFyFx+7/21/2024Statics-Problems-34KylinsoftKylinsoftOWiWcGiGcFyFx7/21/
13、2024Statics-Problems-35KylinsoftKylinsoftP116-4.27:Solution:x=0 7/21/2024Statics-Problems-36KylinsoftKylinsoftxyO2xyO1P131-5.2:解:3036lb20lb18in假设系统是静力平衡的先研究圆柱,有P1G1G2N1N2f2f1P1得再研究方块,有得而因,所以系统不能保持静力平衡7/21/2024Statics-Problems-37KylinsoftKylinsoftP132-5.10:Solution:总体分析: 分析木条 :圆盘分析 :解之得:解之得: NfffCBA.
14、=22.06=达到最大静摩擦力时 :解之得:解之得: 7/21/2024Statics-Problems-38KylinsoftKylinsoft9000N/mBCDBCDP132-5.12:解:P假设系统是静力平衡的先研究桩子CBD,有NBNBNAfAfBRxRy再研究杆AB,有P9000N/m1.5m2m3m0.8mABCDABfBAB7/21/2024Statics-Problems-39KylinsoftKylinsoft只有当fAfAmax或fBfBmax时,杆AB才能移动,由以上计算结果可知,当P6300(N),杆AB在A点处开始移动7/21/2024Statics-Problems-40KylinsoftKylinsoftP133-5.18:Solution:因此因此 :7/21/2024Statics-Problems-41KylinsoftKylinsoftP133-5.19:Solution:木块翻转临界时:滑动时:7/21/2024Statics-Problems-42KylinsoftKylinsoftP134-5.22:当P=600 lb时: 当P=200 lb时: Solution:7/21/2024Statics-Problems-43KylinsoftKylinsoft