交流与评估是科学探究的一个重要环节．建湖外国语学校的活动小组_爱下问搜题

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问题问答题

交流与评估是科学探究的一个重要环节．建湖外国语学校的活动小组的同学，利用如图所示的实验装置完成了“再探动滑轮”的活动以后，进行了小组交流，下表是各小组的实验数据记录：

实验小组	钩码重G（N）	动滑轮重G_动（N）	拉力F（N）	滑轮机械效率η
1	0.5	0.4	0.35	47.6%
2	0.5	0.4	0.38	43.9%
3	1	0.6	1.62	53.8%
4	1	0.8	0.71	46.9%
5	2	0.6	0.98	68.0%
6	2	0.8	1.06	62.9%

请你对表中各小组的实验数据进行分析比较，回答下列问题：

（1）实验中影响动滑轮机械效率的主要因素是什么？______和______；

（2）1、2两个小组的动滑轮重相同，提起的钩码重也相同，测出的动滑轮的机械效率却不同，原因可能是什么？（写出一点即可）

______；

（3）请你就如何提高动滑轮的机械效率提出自己的建议：

①______；

②______．

答案

（1）由3、4或5、6可以看出，钩码重相同，动滑轮越重，机械效率越低；由3、5或4、6可以看出，动滑轮重相同，钩码越重，机械效率越高．

（2）除了动滑轮重力和物体重力影响机械效率外，绳重和摩擦也会影响动滑轮的机械效率．

（3）动滑轮的重力越小、绳重和摩擦越小，动滑轮的机械效率越高．

故答案为：（1）钩码重、动滑轮重；

（2）绳重或摩擦，或者操作不规范；

（3）①减小摩擦，或加润滑油；②减轻动滑轮重，或增加物（钩码）重．

解答题

小亮家上半年（1～6月）用电576千瓦时，平均每个月用电多少千瓦时？

完形填空

Early one morning, I witnessed romance at one the least-expected places in the world—a room in a rest home. At the time, my father 36 a room with three other gentlemen.
Before my daddy lived in the rest home, an elderly 37 was sent there. Since there wasn’t a double room 38 , they were forced to separate the couple. The gentleman, Mr.West, was 39 in the bed beside Daddy. His wife, Mrs.West, shared a room with several other ladies down the hall.
When I went to see Daddy that morning, I 40 Mr.West. Three employees were working with him. He hadn’t eaten a bite of food 41 he was sent several days earlier. I could 42 by the expression on the nurses’ faces that they were worried about him. Mr.West 43 to open his mouth for any of them.
“Go and get Mrs.West, ” the nurse told her helper. “Maybe Mr.West will eat 44 her. ”
In a few minutes a kind-looking lady was 45 into the room. Her smile was contagious（传染的）and Mr.West smiled 46 . I felt as though I was intruding（侵入）on a 47 moment, but I couldn’t take my eyes off the couple. The love between them was obvious, as Mrs.West patted Mr.West’s hand.
With a soft voice, Mrs.West tried to 48 Mr.West to eat. To everyone’s surprise, Mr.West 49 his mouth and began to enjoy the 50 and his wife’s company. While the nurses fed him, he stared at his sweetheart with a smile on his face. Mrs.West began singing a song for him. The 51 on his once solemn（严肃的）face became even brighter.
Tears 52 my eyes. The nurse then 53 the curtain around the couple to give them some quality time alone. I discovered that 54 doesn’t only exist when we’re young and in love. Romance 55 a lifetime and grows stronger with age.

B．acknowledge

A．understood.

C．was opening

B．filled with

D．were filled with