小琦学习了有关声音的知识后,对材料的隔音性能很感兴趣,于是他设计了如下实验进行探

题型:问答题

问题:

小琦学习了有关声音的知识后,对材料的隔音性能很感兴趣,于是他设计了如下实验进行探究.

实验步骤:

(1)先搜集各种材料,如衣服、报纸、平装书、塑料袋、袜子;

(2)把钟放到一个鞋盒里,将衣服盖在盒上方,然后逐渐离盒子直到听不见滴答声,记下此时人离盒子的距离.

(3)分别将各种材料盖在盒上方,重复以上实验,得到下表的数据.

材料衣服报纸平装书塑料袋袜子
听不见滴答声的实际距离2.12.83.75.21.2
回答问题:

(1)小琦设计的实验利用了离声源越远,听到的声音响度越______(填“大”或“小”)的原理.

(2)根据小琦所得数据可知粗糙材料比平滑材料的隔音性能______(填“好”或“坏”).原因是粗糙材料吸收声音的性能要比平滑材料______(填“强”或“弱”).

考点:声速
题型:问答题
Once a beggar(乞丐) had walked about five miles in the hot sun. He was quite tired and wanted to   1 . As he came to a crossing, he saw a tall tree. On one side   2  the tree he saw a board(木牌). “Take This Road To Franklin” was written on the board.
“I will rest under the   3 ,” said the beggar. “I can lie on the board while I sleep.” As the beggar   4 , a doctor rode up to him. “Wake up, beggar!” said the doctor. “I am lost. Can you tell me   5  road to take to Franklin?” “It is too hot to think,” said the beggar. “Thinking is work in such a   6  day.” “Here is a dollar,” said the doctor, “now, will you think?” “Of course, I will, sir!” said the beggar, “  7  that road to Franklin.” After a while, a driver stopped to   8  the beggar which road to take to Franklin. “You must give me a dollar,” said the beggar, “for me to start thinking.” The driver gave him a dollar. “Turn to the left,” the beggar said.
The beggar went back to   9 . Before long a farmer woke him up.
“Which is the road to Franklin?” he asked. The beggar got   10  dollar and the farmer went along the road.
“A doctor gets paid when he doctors.” said the beggar to himself, “A driver gets paid when he drives, and a farmer gets paid when he farms. But this time a beggar got paid, and all he did was thinking!”
小题1:
A.drinkB.eatC.restD.ride
小题2:
A.withB.ofC.byD.for
小题3:
A.treeB.signC.roadD.bed
小题4:
A.thoughtB.saidC.passedD.slept
小题5:
A.rightB.whichC.shortD.only
小题6:
A.warmB.coldC.hotD.wet
小题7:
A.WalkB.TakeC.GoD.Get
小题8:
A.tellB.showC.askD.help
小题9:
A.sleepB.workC.readD.write
小题10:
A.threeB.moreC.paidD.another
题型:问答题

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题型:问答题

你知道根的什么部位长得最快?(  )

A.根冠

B.生长点

C.伸长区

D.成熟区

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舟骨骨折,可分为结节部骨折、腰部骨折、近端骨折,骨坏死机会较多的位于().

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