如图所示在点电荷 +3q 和 -q 的静电场中，做如下三个闭合面S1、S2、S3。
则通过S1、S2、S3闭合面的电通量分别为：( )
A:
B:
C:
D:
则通过S1、S2、S3闭合面的电通量分别为：( )A:
B:
C:
D:
举一反三
- 在常体力的情况下，平面问题的应力函数与应力分量之间的关系正确的有（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/13db38e0be0f42a8aa8220026ad6d3e5.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/9178e461e0974317b42e0e9b59149047.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/d66f684595a1482283e180c311c9e8f4.png"> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/20a366b5fd844f65a1716a7a6078b968.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/f4a5a69f1a264e5b8f28fa968022cbb0.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/b77e7d17deb548619be88f5ed437af81.png"> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/cb0ce22cc89447b5b3a914b1a55209a0.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/d56afcca319e46a2be256f91ac5e289b.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/d6a4d2e83f9448cdbfec37887ffd53a9.png"> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/1f5fa1a13a4c48698715e2b1814291b4.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/06c0cb7f6e184b18a6b345acff91e4bb.png">，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/c59f70ea241546dd948d2f09b5821ac6.png">
- 若某系统的传递函数为G(s)=<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/79eaf52d33de48cd9c870f2ce2ace2dc.png" />，则其频率特性的实部R(ω)是（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/22de2385b19e4de8be5ae000bddad620.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/4a873e7d91b44c11bad767efd2747b11.png" /> C: -<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/4a873e7d91b44c11bad767efd2747b11.png" /> D: -<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/22de2385b19e4de8be5ae000bddad620.png" />
- 下面和声连接对的是（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/cfbbaacbd31140caada6de1a82879cf1.jpeg" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/cfbbaacbd31140caada6de1a82879cf1.jpeg" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/cfbbaacbd31140caada6de1a82879cf1.jpeg" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/cfbbaacbd31140caada6de1a82879cf1.jpeg" />
- 双纽线<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/ac4dfd0de9744513843c41341938f31c.png" />所围成的区域面积可用定积分表示为（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/b3a266adc8704187b18601cd19efc069.png" /> <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/fbc5959fd78d4d09ae216f05e45741c0.png" />. <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/02b5a6e0e400485382b137795ebb9ef1.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/45fb209600124a569d31e4c0ed4264f9.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/d5291bc308bc4880919d6f34ce4f7539.png" />
- 下列不属于弹性力学平面问题的是（ ）。 A: 应力分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/14e55ab2cde14d22a44bff9ea88507d2.png">，只有应力分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/c3c1da2ca4e64ad19e0fbc1764ed6bcc.png">存在，且它们都仅为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/7bffc15d98b240c584d659d1aa155670.png">和<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/dbee1ba1e52447b2bb076c7d812d3e5c.png">的函数 B: 应变分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/ea8a2b953bca4b598b6781db39c5f5bf.png">，只有应变分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/7877a5c9731d4b54b054875be6f3ea05.png">存在，且它们都仅为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/7bffc15d98b240c584d659d1aa155670.png">和<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/dbee1ba1e52447b2bb076c7d812d3e5c.png">的函数 C: 位移分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/1e6aeef29fa74143bf306acfc598d7e4.png">，只有位移分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/0a59276fcf7e48d8bc4d1fb7313cc78d.png">存在，且它们都仅为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/7bffc15d98b240c584d659d1aa155670.png">和<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/dbee1ba1e52447b2bb076c7d812d3e5c.png">的函数 D: 薄板弯曲问题