试题与答案

如图所示,光滑斜面、光滑水平面Ⅰ、光滑水平面Ⅱ及紧靠水平面Ⅰ的长木板M,木板上表

题型:问答题

题目:

如图所示,光滑斜面、光滑水平面Ⅰ、光滑水平面Ⅱ及紧靠水平面Ⅰ的长木板M,木板上表面与水平面Ⅰ齐平,动摩擦μ=0.4.物块m1从高为h=7.2m处由静止释放无机械能损失滑到水平面Ⅰ,与m2碰后立即粘为一体,两物块滑到木板右端时恰好与木板相对静止.已知:m1=m2=1kg,M═4kg,g=10m/s2.求:

①物块m1与物块m2碰后,两物块的速度大小;

②木板的长度L.

答案:

①(1)设物块m1由静止滑到光滑水平面Ⅰ上时的速度为v1,由机械能守恒得:

m1gh=

1
2
m1v12

代入数据解得:v1=12m/s,

以两物块组成的系统为研究对象,两物块碰撞过程动量守候,以向右为正方向,由动量守候定律得:

m1v1=(m1+m2)v2

代入数据解得:v2=6m/s;

②两物块滑上木板后,以物块与木板组成的系统为研究对象,以向右为正方向,由动量守恒定律得:

(m1+m2)v2=(m1+m2+M)v3

代入数据得:v3=2m/s,

由能量守恒定律得:μ(m1+m2)gL=

1
2
(m1+m2)v22-
1
2
(m1+m2+M)v32

代入数据解得:L=3m;

答:①物块m1与物块m2碰后,两物块的速度大小为6m/s;

②木板的长度为3m.

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题型:阅读理解

If Confucius(孔子)were still alive today and could celebrate his September 28 birthday with a big cake, there would be a lot of candles. He’d need a fan or a strong wind to help him put them out.

While many people in China will remember Confucius on his special day ,few people in the United States will give him a passing thought. It’s nothing personal. Most Americans don’t even remember the birthdays of their own national heroes.

But this doesn’t mean that Americans don’t care about Confucius. In many ways he has become a bridge that foreigners must cross if they want to reach a deeper understanding of China.

In the past two decades, the Chinese studies programs have gained huge popularity in Western universities. More recently, the Chinese government has set up Confucius Institutes in more than 80 countries. These schools teach both Chinese language and culture. The main courses of Chinese culture usually include Chinese art, history and philosophy(哲学).Some social scientists suggest that Westerners should take advantage of the ancient Chinese wisdom to make up for the drawbacks of Western philosophy. Students in the United States, at the same time, are racing to learn Chinese. So they will be ready for life in a world where China is an equal power with the United States. Businessmen who hope to make money in China are reading books about Confucius to understand their Chinese customers.

So the old thinker’s ideas are still alive and well.

Today China attracts the West more than ever, and it will need more teachers to introduce Confucius and Chinese culture to the West.

As for the old thinker, he will not soon be forgotten by people in the West, even if his birthday is.

小题1:The opening paragraph is mainly intended to   .

A.provide some key facts about Confucius

B.attract the readers’ interest in the subject

C.show great respect for the ancient thinker

D.prove the popularity of modern birthday celebrations小题2:We can learn from Paragraph 4 that American students   .

A.have a great interest in studying Chinese

B.take an active part in Chinese competitions

C.try to get high scores in Chinese exams

D.fight for a chance to learn Chinese小题3:What is the best title for the passage?

A.Forgotten Wisdom in America

B.Huge Fans of the Chinese Language

C.Chinese Culture for Westerners

D.Old Thinker with a Big Future小题4:The passage is likely to appear in   .

A.a biography

B.a history paper

C.a newspaper

D.a philosophy textbook

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