时，振子在位移为处，且向负方向运动，则初相的旋转矢量为（）https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/e82b75f1ea6244eab45f418066e8bb59.gif
举一反三
- 如图所示电路的逻辑表达式F=（ ）。<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/8655693a417e4e43a32e0732ed533c96.png" /> A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/beda73211aea49f082d9137fd4eb0526.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/7388c99ee0824f20bcf85893934a2f6a.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/9a5c81e78b344c79a9389e932a7f55ce.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/82193a9a030243728012b02e15718987.png" />
- 体系处于<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/7bae90aad0f0442d9d6adf4ff4c69c2c.png" />状态,则体系的动量取值为 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/156065cb1de5431a9a2ea0b029f26f79.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/627120343f054317828addfe01200e5b.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/09f88938fc6f43a0819284117c0b14fa.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/2311487532fb45c789f7dce939291db1.png" />
- 如图示并联管路，已知各支路的沿程阻力系数之比为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/6e209020d20f4543823ce6516ae8ca06.png" />，管长之比为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/50814fe028094040bc955d8e1542b6d2.png" />，且<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/40b4c6a9565b483590c5c7d607e7ed66.png" />，则两支管的流量之比<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/1055534bfce6426a94682ba086a5b17e.png" />=（）。<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/77815369f5cd41f3a2e68b9524b454c5.png" /> A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/0cd231eebe45465f941a0f614743e6d2.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/7555afa5223e40bf89ca575cf7b52754.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/1b06cd474b844644a6d97ad87d208e94.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/d0b2bca045414236a7d1c9925a9264f2.png" />
- 若电路的电压为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/993b4b3ea33847708c2eb8347678fac3.jpg" />电流为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/3242804b93af486198ca23f1839f1a1a.jpg" />，则 i滞后u的相位角为75°。 （ ）
- 线性谐振子的第一激发态的波函数为<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/aab7a58985f443ed91a9f4036d4b56dd.png" />,其位置几率分布最大处为 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/44c963c6379540a099bfd79da6501b42.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/dff9139c15174797b8b68ef230d1ee90.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/ad088197932f430db9416ebf9d5b47fa.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/17949074010c4d44ad48b416055aaa86.png" />