【单选题】
下图所示三铰拱,拉杆AB拉力为( )。<img src="20200804/1596521992600762.png" title="1596521992600762.png" alt="图片4.png"/>
【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/92937B70ECBCEACE925CAD085D6DAFD6.png title=4.png alt=4.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/D0430E27D605015C752493220B8E98E4.png title=4-1.png alt=4-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/8A554B979CB6B7F140B62F660574BBE4.png title=4-2.png alt=4-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/5F1A24467347180989EAA9A31FDE2D6D.png title=4-3.png alt=4-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/F88F9E70F75F85B938ECE77D72D92CCA.png title=4-4.png alt=4-4.png/>
【单选题】
已知向量<img src="20190809/1565318424536224.png" title="1565318424536224.png" alt="图片12.png"/>的长度为3,方向向东,向量<img src="20190809/1565318432803809.png" title="1565318432803809.png" alt="图片11.png"/>的长度为4,方向向北,则<img src="20190809/1565318416857876.png" title="1565318416857876.png" alt="图片10.png"/>等于( )
①
<img class="kfformula" src="20190809/1565318471610307.png" data-latex="5"/>
②
<img class="kfformula" src="20190809/1565318471807250.png" data-latex="7"/>
③
<img class="kfformula" src="20190809/1565318471275858.png" data-latex="11"/>
④
<img class="kfformula" src="20190809/1565318471551260.png" data-latex="\sqrt {73}"/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/61677886C169EFB29FBB1CAD3E134649.png title=4.png alt=4.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/BF3FDF7526E6F4DF464E7E6AB2B147BF.png title=4-1.png alt=4-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/95DAC9EC41FCFF7F96D45E23A2933AFB.png title=4-2.png alt=4-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/F8EC99EEE11CF0D54CDDA810C35EEA9E.png title=4-3.png alt=4-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/009309296B15B1ACDA8B77FAF1106928.png title=4-4.png alt=4-4.png/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/B93830581AB669EE76FE45AEEB75EACC.png title=4.png alt=4.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/7223AD0D4F73ED8B5730F8843FD68AD5.png title=4-1.png alt=4-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/FA1A0B6530E9C8CABF5FE5DEE30CEB96.png title=4-2.png alt=4-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/A7973D043814219EA5F2AF98BC67F2B0.png title=4-3.png alt=4-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/F99F0B04846FFE48A4865EA5BFA0BFD0.png title=4-4.png alt=4-4.png/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/86BA88713E99791F6245FF5DB76637B4.png title=4.png alt=4.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/C68E9B3FD3E7621C39C718D63AB3F513.png title=4-1.png alt=4-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/6DF94C6405C0E9C3B4B2D41AFA7E70CF.png title=4-2.png alt=4-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/39414C336FD06C9612C8912AB60671BF.png title=4-3.png alt=4-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/034F12DB164BD508DF7F90EA26D901AC.png title=4-4.png alt=4-4.png/>
【单选题】
<img src=https://huaweicloudobs.ahjxjy.cn/CE438FFA8937454B38C0DE9C1750383A.png title=4.png alt=4.png/>
①
<img src=https://huaweicloudobs.ahjxjy.cn/4C7B7F274236552013503AD72645C174.png title=4-1.png alt=4-1.png/>
②
<img src=https://huaweicloudobs.ahjxjy.cn/A75671EE2CE0AE0563FCB3CE16ABE5CC.png title=4-2.png alt=4-2.png/>
③
<img src=https://huaweicloudobs.ahjxjy.cn/C38718C1834818D48061D4B34FD05914.png title=4-3.png alt=4-3.png/>
④
<img src=https://huaweicloudobs.ahjxjy.cn/96D982B8E3E7195EA7A3F24375E88F73.png title=4-4.png alt=4-4.png/>
【单选题】
<img src="20190730/1564476408892116.png" title="1564476408892116.png" alt="图片102.png"/>等于 ()
②
<img src="20190730/1564476424383415.png" title="1564476424383415.png" alt="图片103.png"/>
【单选题】
下图表示的是钢制柱式散热器型号表示方法 ( )。<img src="20190823/1566522127776052.png" title="1566522127776052.png" alt="图片4.png" width="361" height="316"/>