【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/E285729361C8255EED427B6769C26599.png title=4.png alt=4.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/3921DA6BF6A228B85831C66C596A50C6.png title=4-1.png alt=4-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/96890382153F88A88887663E157497EB.png title=4-2.png alt=4-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/0CDE5B7F13D5136BA1E33FEEA409E4D3.png title=4-3.png alt=4-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/DBDDB437DA76FDDF816E204D8AF1F37D.png title=4-4.png alt=4-4.png/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/5D4CBB356F877148D6449048522A2185.png title=4.png alt=4.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/A2DABF38F3AF3B36DBF025AA23F4F807.png title=4-1.png alt=4-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/088A007A927A0EC33B29E097EFD64EE3.png title=4-2.png alt=4-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/83769A66D5DA963CFC6AF9985C6276EA.png title=4-3.png alt=4-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/D208CC045685F7F275B258045772D36E.png title=4-4.png alt=4-4.png/>
【单选题】
<img src=http://60.205.157.60/course/a@F87801D9001E1076D65A77D630877600.jpg title=单选题图5.jpg alt=单选题图5.jpg/>正方形结构如图5所示，已知各杆的EA都相同，则斜杆1-3的伸长为( )。
①
Δl=2Fa／EA
②
Δl=0
③
Δl= Fa／2EA
④
ABC均错
【判断题】
<img src=https://huaweicloudobs.ahjxjy.cn/BC6BE4E96DA1F46217B66358B0B55D94.png title=4.png alt=4.png/>
①
正确
②
错误
【判断题】
<img src=https://huaweicloudobs.ahjxjy.cn/B19661C941268DA2F18DE7B87080983E.png title=4.png alt=4.png/>
①
正确
②
错误
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/50A7613D65079122BDD05186B1D547A2.png title=4.png alt=4.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/17D45722468C2304E927A7863DAB9320.png title=4-1.png alt=4-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/83AD93FD147A07F52F7442E977A2D5E8.png title=4-2.png alt=4-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/B149EB543D873852CFE1B7CF2489501F.png title=4-3.png alt=4-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/F85B4AC6FFDC77E75AC37228B15C5C4C.png title=4-4.png alt=4-4.png/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/E63EFDD38D8A922C2D63C3CBE7D338ED.png title=4.png alt=4.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/4F4E038E5E379044FFDBB50A199D4BB0.png title=4-1.png alt=4-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/A7395CE44F69E3E165B8B2FD0C61CCAF.png title=4-2.png alt=4-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/9EBBB23187468B7B9426724DFA5F38BC.png title=4-3.png alt=4-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/F5D4F542D8397031121A84DBDC1DB6FE.png title=4-4.png alt=4-4.png/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/48A8FC7CAC0BA5ED5F09E1281C2885DA.png title=4.png alt=4.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/1CEA2855311D171C0BA2F1174CFBC3BF.png title=4-1.png alt=4-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/31258A15223174121D71E615E88765D3.png title=4-2.png alt=4-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/8468B797B67C04F9FA273FE638CA6B5A.png title=4-3.png alt=4-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/B54CADE670BF7BC5D12AFE5ABD3E0618.png title=4-4.png alt=4-4.png/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/1E8A240E8C1F631E82009065386C57BE.png title=4.png alt=4.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/027300C3180166A26EAD35F0AE85E539.png title=4-1.png alt=4-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/8103A3A2DA9C5898A2B0FDF5CA8894BA.png title=4-2.png alt=4-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/A36F2ABFD25E1D228485204109F11451.png title=4-3.png alt=4-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/34586DC435F0A13039CD7653EBBB62C0.png title=4-4.png alt=4-4.png/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/ED7B3988571DCEF095E67E455A81D9FE.png title=4.png alt=4.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/3322533243ADAB58240B78A0EB9B3867.png title=4-1.png alt=4-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/F2B8B38A97AFF2AAA58D5B654ABC97E9.png title=4-2.png alt=4-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/FAAC16322A145A406EB257B495E2238F.png title=4-3.png alt=4-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/C184C43B498566791AB16657E364A9B1.png title=4-4.png alt=4-4.png/>
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