如图所示，均质细杆AB和BD用光滑铰链B连接，A端为固定铰链支座，系统在铅垂平面内运动。已知两杆质量均为m，长均为l。图示位置时，杆AB水平，杆BD与铅垂方向的夹角为30°。当系统在图示位置无初速释放的瞬时，以下关于杆AB和杆BD的角加速度的大小正确的是（ ）。A:
B:
C:
D:
举一反三
- 图示平面机构中，半径为R的圆轮C以匀角速度ω绕O轴沿逆时针转动，并带动AB杆绕A轴转动。在图示瞬时，AB杆水平，CD铅垂，OC与铅垂线的夹角为60°，点O、C、A在同一直线上。则此时AB杆的角速度和角加速度分别为（ ）。<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/af3815c61a564a70a048c1bf0772aa2f.png"/> A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/a0a72ae9effa478fa68736a4b3b3f1ec.png"/> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/80786628e936475a81445701858a9e09.png"/> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/31fe018322374901a18aa2662e50691e.png"/> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/3b771d7e1c1943cabb08819b15009c85.png"/> E: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/0b2c8118e3c2404598cb429ddc5096cf.png"/> F: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/a7f6e85ef3ad4b748e6367370bec567b.png"/>
- 图示匀质细杆AB和BC的长均为l，质量均为m，两杆用铰链B联结，并悬挂在固定铰链支座A上。今在B点作用一水平力F，使系统由静止进入运动，则此瞬时两杆的角加速度为（ ），假设逆时针为正。<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/8d1345b465b24503bdd122d3389e3967.png"/> A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/ca5a7e7d7dd24789a7b1a452fc4f03c8.png"/> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/7005f6bf869e4afea2c04ee479b4a291.png"/> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/2d8e34f3121443cba35c501577fbb4d3.png"/> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/cb181a8560ae49f4b98519b8a7fdd9cd.png"/>
- 开环系统频率特性<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/d87c0f560f1542028a3602b52456fae0.png" />，当<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/c0f50539680f40a784c2a0d803f0f5d7.png" />时，其频率特性相角<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/ff41a81bec7c421c8178de199c438e05.png" />（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/589b5e2ab46b459882a2824ff9567c36.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/370b677492de485ca61114324b5d00fe.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/95723a2a938f4944a98b18d89f607986.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/c08161009369424f9a3510d7c77d9943.png" />
- 下列方程为伯努利方程的是（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/0622f56257874ab19e680d587fd8a4fc.png"> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/5ce3fc785b724e3da7d07b8d6a0ecaf3.png"> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/ab3de1c35e9e419fa301a33bddd5ee0c.png">+<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/2c226f2daecf40448b08c3b26a4db60e.png"> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/88be95dd74814341a1894f32f073b9ec.png"><img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/00fbcbc7c3574f94934fa3adc8843ccf.png">
- 直线<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/64709df03a7b45ebbc6d752183b8f22e.png" />与直线<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/5ca5aa44859c42ddaa3207626d2b9537.png" />的公垂线方程为（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/a4c463fa2c3f49df9d7f2bb2e9fc4030.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/627b64a33e944efcba416aea0f40dc76.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/966e8a14e6754060b800dff88721784a.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202108/f8f41491de204a9eb3fb306208c3b08a.png" />