题干

在学习吉他演奏的过程中,小明发现琴弦发出声音的音调高低受各种因素影响,经过与同学们讨论,提出了以下猜想:

猜想1:琴弦发出声音的音调高低,可能与琴弦的横截面积有关;

猜想2:琴弦发出声音的音调高低,可能与琴弦的长短有关;

为了验证上述猜想是否正确,他们找到下表列出的几种规格的琴弦进行实验.则:

编号

材料

长度/cm

横截面积/mm2

A

20

0.3

B

20

0.7

C

尼龙丝

30

0.5

D

40

0.5

E

尼龙丝

40

0.5

(1)为验证猜想1,应选编号为____ ____ 的琴弦进行探究.

(2)为验证猜想2,应选编号为____ ____ 的琴弦进行探究

(3)随着实验的进行,小丽又觉得琴弦音调的高低还可能与琴弦的松紧程度有关,为了验证这一猜想,请写出你的操作过程:____ 

上一题 下一题 0.0难度 选择题 更新时间:2019-04-17 08:52:01

答案(点此获取答案解析)

A,B,C,E,选择一根琴弦,调节弦的松紧程度不同,用相同的力拨动它,听它发出声音的音调高低

同类题2

阅读理解。

阅读短文,从每题所给的四个选项(A、B、C和D)中,选出最佳选项。

    Camping wild is a wonderful way to experience the natural world and, at its best, it makes little environmental influence. But with increasing numbers of people wanting to escape into the wilderness, it is becoming more and more important to camp unobtrusively(不引人注意地)and leave no mark.

    Wild camping is not permitted in many places, particularly in crowded lowland Britain. Wherever you are, find out about organizations responsible for managing wild spaces, and contact them to find out their policy on camping and shelter building. For example, it is fine to camp wild in remote parts of Scotland, but in England you must ask the landowner's permission, except in natural parks.

    Camping is about having relaxation, sleeping outdoors, experiencing bad weather, and making do without modern conveniences. A busy, fully-equipped campsite(野营地)seems to go against this, so seek out smaller, more remote places with easy access to open spaces and perhaps beaches. Better still, find a campsite with no road access: walking in makes a real adventure.

    Finding the right spot to camp is the first step to guaranteeing a good night's sleep. Choose a campsite with privacy and minimum(最小化的) influence on others and the environment. Try to use an area where people have obviously camped before rather than creating a new spot. When camping in woodland, avoid standing dead trees, which may fall on a windy night. Avoid animal runs and caves, and possible homes of biting insects. Make sure you have most protection on the windward side. If you make a fire, do so downwind of your shelter. Always consider what influence you might have on the natural world. Avoid damaging plants. A good campsite is found, not made—changing it should be unnecessary.