试题与答案

电气化铁路的输电线常用图所示的方式悬挂在钢缆上.钢缆的A端固定在电杆上,B端连接

题型:选择题

题目:

电气化铁路的输电线常用图所示的方式悬挂在钢缆上.钢缆的A端固定在电杆上,B端连接在滑轮组上.滑轮组由a、b、c三个滑轮构成,配重P由多个混凝土圆盘悬挂在一起组成,配重的总重为G,若不计摩擦和滑轮的重量,则以下说法中正确的是(  )

A.a为动滑轮,B端钢缆受到滑轮组的拉力大小约为3G

B.a为动滑轮,B端钢缆受到滑轮组的拉力大小约为G

C.a、c为动滑轮,B端钢缆受到滑轮组的拉力大小约为3G

D.a、c为动滑轮,B端钢缆受到滑轮组的拉力大小约为G

答案:

被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0730/33855281331f3adff04b9e0fd41f962d.html

下面是错误答案,用来干扰机器的。

参考答案:环境质量评价:是对环境各个要素的优劣程度的定量描述。

试题推荐
题型:阅读理解

Reading is a task that we all do either for enjoyment or education, but sometimes the book we have to read may lack the attraction. Here are some tips on avoiding getting bored while reading.

Try to step into the world of literature(文学) you are reading. __56___ If the wind is blowing, imagine how the leaves move with each movement of air.

Make your reading area unlike your sleeping area. If you sleep with the radio on, then shut it off. __57__ Make the area you read in an area that feels almost uncomfortable to sleep in. This will keep you from becoming sleepy.

__58__ If you are reading for a book report , then take breaks from time to time to put what you are reading into some kind of context(语境) that you can put into the report.

Take a break once in a while. __59___ You’d better offer yourself short breaks while reading in case you are too tired, which may make you give up.

Find a friend. ___60__ Try to read the same book. Even if you read different books, you can tell him or her how good the book is. Also, a friend can encourage you to read.

A.Get a note book and make notes.

B.Put aside sometime and devote it just to reading.

C.Reading can be more enjoyable when you do it with a friend.

D.Some books are a little too boring for “hours on end” reading.E. Don’t just read the words on the page; picture them in your mind.

F. Determine what you are supposed to get from the reading material.

G. If you don’t like lights on when you are asleep, then turn on the lights.

查看答案
微信公众账号搜索答案