问题 实验题

同一水平桌面上放有长方体木块和铁块各一个.现想探究木块和铁块的下表面谁更粗糙,请你只利用一个量程满足实验要求的弹簧测力计,设计一个实验来验证你的猜想.写出实验的步骤和分析实验的结果.

答案

实验步骤:

(1)将铁块放在木块上,用弹簧测力计水平匀速拉动木块,记下测力计示数F1。(1分)

(2)将木块放在铁块上,用弹簧测力计水平匀速拉动铁块,记下测力计示数F2。(1分) 

实验结果:若F1> F2,则木块下表面粗糙;若,则可以得出铁块下表面更粗糙。(1分

分析:因为滑动摩擦力的大小与压力大小和接触面的粗糙程度有关,所以要探究接触面的粗糙程度,需要控制压力大小相同.因此可以想办法使两个物体叠放起来.

解答:答:实验步骤:(1)将铁块放在木块上,用弹簧测力计水平匀速拉动木块,记下测力计示数F1

(2)将木块放在铁块上,用弹簧测力计水平匀速拉动铁块,记下测力计示数F2

实验结果:若F1>F2,则木块下表面粗糙;若F1<F2,则可以得出铁块下表面更粗糙

阅读理解

     Once upon a time, there was a little weasel (鼬鼠). His name was Horace. Unlike all the other

weasels, Horace was very bookish.

     He had a copy of The Little Prince that he had found out behind a chicken house. The third chapter

of the book was missing and the back cover was broken, but it was the only book he had, and he loved

it. While all the other weasels spent their time playing, Horace would read instead. This made the other

weasels surprised, but they let it go by.

     Then, one day, the Earth was invaded (入侵) by space aliens. These aliens were a group of giant

librarians. Because they were librarians, they had of course done their research before they began their

invasion.     

     Meanwhile, the librarians went out to make contact with the species with whom they felt the most

affinity (密切关系). They had hoped that they could find the great works of weasel literature, but they

found that this was not so. The giant weasel librarian aliens were very disappointed. "Is there no weasel

at all who loves books as we do?" (Naturally, they had learned to speak the weasel language.) "No,"

said the weasels.

     At last, they came to the town where Horace lived. Here the weasels said "Yes!" They found Horace

and placed him in their libraries, where at last he got a complete edition of The Little Prince. He read it

every day for the rest of his life.

1. From the text we can infer that        .

A. Horace had a copy of The Little Prince

B. the space aliens looked much like weasels

C. the space aliens hate weasels

D. Horace and the space aliens had the same hobby

2. Which of the following is TRUE about Horace?

A. Horace liked playing with other weasels.

B. Horace got a book behind a chicken house.

C. Horace read the book when other weasels took a rest.

D. Horace lived in the town with the librarians.

3. According to the text, give the right order of the following events.

a. The space aliens found Horace and gave him a job as a librarian.

b. Horace had a copy of The Little Prince but it was broken.

c. The space aliens had done their research before they began their invasion.

d. The space aliens went to look for a weasel who loved reading books.

A. a, b, c, d  

B. b, a, c, d,  

C. b, c, d, a  

D. c, a, b, d

4. The underlined word "bookish" probably means "          ".

A. foolish  

B. fond of reading

C. childish    

D. selfish

5. The text above is a (n)        .

A. fairy tale  

B. scientific report

C. poem  

D. essay (随笔,小品文)

判断题