A1v1= A2v2 ( 2-19 ) 或写成 q=vA= 常数 应用:式( 2-19 )即为液流连续性方程,它说明液体在管道中流动时,流 经管道每一个截面的流量是相等的,并且同一管道中各个截面的平均流速与过流断面面积成反比,管径细的地方流速大,管径粗的地方流速小。 式( 2-19 )表明: 液体在管道中流动时,流经管道每一个截面的流量是相等的(这就是液流连续性原理)并且同一管道中各个截面的平均流速与过流断面面积成反比,管子细的地方流速大,管子粗的地方流速小。
高中英语必修一外研版67页1到4题
原题:
答案:
1大题与2大题(括号里的数字是2大题的答案)
1.study(2)
2.are studying(5)
3.use(2)
4.play(2)
5.are doing(4)
6.are learning(5)
7.starts(1)
8.rises(3)
3大题(此题无标准答案,每个学生有自己不同的答案。这儿提供的答案只有一个样本而已)
1.We don't study chemistry on Fridays.
2.We never study Russian this term_
3.We don't use the computer once a week. We use the computer twice a week.
4.I never play football after school on Mondays.
5.I'm not doing my homework now.
6.无需改写.
7.Our school doesn't start at 9 am every day. Our school starts at 7 am every day.
8.无需改写.
4大题
1.Where do you live?
2.What are you writing now?
3.What language are you studying this term?
4.What do you think of the people at your school?
5.What kind of food do your family eat at the weekend?
6.What is the person next to you doing now?