问题 多选题
如图所示,在倾角为θ的光滑斜面上,存在着两个匀强磁场,磁场Ⅰ垂直斜面向上、磁感应强度大小为B,磁场Ⅱ垂直斜面向下、磁感应强度大小为2B,磁场的宽度MJ和JG均为L,一个质量为m、电阻为R、边长也为L的正方形导线框,由静止开始沿斜面下滑,当ab边刚越过GH进入磁场Ⅰ区时,线框恰好以速度v1做匀速直线运动;当ab边下滑到JP与MN的中间位置时,线框又恰好以速度v2做匀速直线运动,从ab进入磁场Ⅰ至ab运动到JP与MN中间位置的过程中,线框的机械能减少量为△E,重力对线框做功的绝对值为W1,安培力对线框做功的绝对值为W2,下列说法中正确的是(  )

A.V1:V2=4:1

B.V1:V2=9:1

C.△E=W1

D.△E=W2

答案

AD

单项选择题 共用题干题
完形填空

第二节:信息匹配(共5小题,每小题1.5分,满分7.5分)

下面是有关植物和园艺方面的详细信息,请阅读下面相关信息,并按照要求匹配信息。

36. (Part One) Once your plants are growing you will need to keep them happy. How do you do this and what sorts of tools will you need? Plants need water and food, but when and in what sort of quantities? This module explains the cultivation techniques necessary to keep your plants in fine fettle. There are simple basic steps you can take to ensure you cut the right stem, at the right time, in the right place.

37. (Part two) Plants lose water through their leaves all the time. It is essential to ensure there is enough to replenish the roots, otherwise they will die. In warm weather water is lost from the soil by evaporation, so watering will need to be done more often.

38. (Part Three) To keep them growing healthily, plants absorb through their roots about 30 different nutrients and minerals dissolved in water.

39. (Part Four) Pruning is basically cutting off carefully selected parts of a plant to restrict its size, persuade it to grow in a particular shape, encouraging more fruit, flowers or stems, or to remove dead or diseased material. But pruning is neither difficult nor complicated; in fact a lot of it is applying common sense! You just have to follow a few guidelines and check in a book what kind of pruning the particular plant needs. The removal of dead, diseased, broken, crossing and crowded branches is often sufficient for many plants.

40. (Part Five) A spade is your basic digging implement; use it to make holes and to dig sandy or loamy soil. Fork is perfect for digging soil that’s stodgy, such as clay, or full of stones; moving and spreading organic matter; and breaking down clods of soil…

请阅读以下相关主题,然后匹配和其相关的章节:

It tells us how to take care of our garden to make the plants and flowers fairly good.

It tells us that in order to grow well, plants also need all kinds of nutrition, and so how to feed the plants is also important.

That part tells gardeners how to do pruning that can remove the unneeded parts of many plants.

It tells the importance of watering in gardening, especially in hot summer seasons.

That part introduces the tools and different functions of various tools you may use in gardening.

This section presents where you can buy good seeds and it also offers the regular price for you.

有关章节                           主题内容  

36. Part One                       

A.how to take care of garden

37. Part two

B.how to feed the plants

38. Part Three

C.how to prune

39. Part Four

D.the importance of watering40. Part Five                      E. introduces different functions of tools

F. where you can buy good seeds