问题 问答题

图为“碰撞中的动量守恒”实验装置示意图.

(1)入射小球1与被碰小球2直径相同,均为d,它们的质量相比较,应是m1______m2

(2)为了保证小球做平抛运动,必须调整斜槽使______.

答案

(1)在小球碰撞过程中水平方向动量守恒定律故有m1v0=m1v1+m2v2

在碰撞过程中动能守恒故有

1
2
m1v02=
1
2
m1v12+
1
2
m2v22

解得v1=

m1-m2
m1+m2
v0 

要碰后入射小球的速度v1>0,即m1-m2>0,

故答案为:>.

(2)要小球做平抛运动,则斜槽的末端必须水平.

故答案为;其末端切线水平.

故本题的答案为:

(1)>,

(2)其末端切线水平.

阅读理解

阅读理解。

Dear Zhou Lan ,

     Thank you very much for your mail. I want to go to China. I know something about China from your

e-mail. Your English is very good. But I don't know much Chinese. Now I'm learning (学习) it from my

parents. They know much about China. They tell me many things about China.

     I'm happy to know you like your school and your family. You want to know my family and my school.

I have a big family. My grandparents and my parents are all very fine. My father has a brother. He is my

uncle, John. He and my aunt have their children. They're Bill, Linda, Mary and Lily. My brother Dick

is a boy of eighteen. I like my family very much. I'll go to China next year with my mother. She is going

to teach English in a middle school in Beijing.

                                                                                                                                                  Yours,

                                                                                                                                                   Annie

1. This is an e-mail from _____ to_____.     

A. Zhou Lan; Annie            

B. Annie; Zhou Lan 's family

C. Zhou Lan; Annie's family      

D. Annie; Zhou Lan

2. Does Annie's father have any sister?

A. Yes, he has one.              

B. No, he doesn't.

C. Yes, he has two.              

D. No, but he has a brother.

3. How many people, are there in Annie's big family.          

A. 4.        

B. 6.        

C. 12.          

D. 14

4. Who will come to China?        

A. Annie.                      

B. Annie's family.

C. Annie and her mother.          

D. Annie's parents.

5. Who teaches Annie Chinese?       

A. Zhou Lan.                    

B. Annie's parents.

C. Annie's grandparents.          

D. Annie herself.

单项选择题 A1/A2型题