某变径管的雷诺数之比，则其管径之比为（）。https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/4c46a5b24a004e54be6d53f4ab76db13.png
举一反三
- 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" />
- 某变径管两断面的雷诺数之比为1/4，则其管径之比为（）
- 如图示并联管路，已知各支路的沿程阻力系数之比为，管长之比为，且，则两支管的流量之比=（）。https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/6e209020d20f4543823ce6516ae8ca06.png
- 已知某网络函数单位冲激响应如图所示，则网络函数表达式可能为（ ） 。<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/1ea32deea3ff4a79adbdf2fd1d50f685.png" /> A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/3daa0643dbc0480582ecdded649049b2.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/38da044f0efb404a840b6cad69f53996.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/97e060f9767b46cbaa03ec6a04f8baed.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/fc42e852a3ca49ff9fcb9d5efe69a1a9.png" />
- 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" />