两根直径分别为dA、dB的圆形管道,且dA>dB,两管道中流过同种流体,则它们的临界 发布时间:2017-01-15 08:40 │ 来源:www.tikuol.com 题型:单项选择题 问题: 两根直径分别为dA、dB的圆形管道,且dA>dB,两管道中流过同种流体,则它们的临界雷诺数()。A.ReAc>ReBcB.ReAc<ReBcC.ReAc=ReBcD.不能确定
题型:单项选择题 I called Mary many times yesterday evening, but I couldn't get through. Her brother _____ on the phone all the time! [ ]A. was talking B. has been talking C. has talked D. talked 查看答案
题型:单项选择题 下面说法中,错误的是A.单位质量的某种物质,温度升高1℃所吸收的热量叫做这种物质的比热B.单位质量的某种物质,温度降低1℃所放出的热量跟温度升高1℃所吸收的热量相等C.吸收热量越多的物体,这种物质的比热越大D.每种物质都有自己的比热,比热是物质的一种特性 查看答案