问题 选择题

一煤块由静止放到水平向右匀速运动的白色传送带上,煤块在传送带上划出一段黑色的痕迹,若以传送带为参考系,则煤块在传送带上划痕的过程可描述为(  )

A.向右做匀加速运动

B.向右做匀减速运动

C.向左做匀减速运动

D.向左做匀加速运动

答案

答案:C

题目分析:煤块先向右匀加速运动,当速度与传送带相同时,一起匀速直线运动;以传送带为参考系,煤块有向左的初速度,又受到向右的滑动摩擦力,故向左做匀减速直线运动,直到与皮带相对静止;

故选C.

点评:本题关键是先分析清楚煤块相对地面的运动情况,然后再以皮带为参考系,分析清楚煤块的运动情况

阅读理解

阅读理解。

     I'll tell you a story about a Chinese student. It happened when he studied in England. His family name

was Sun. It is spelt S-U-N, just the same as the English word "sun", the sun in the sky.

     England is a country with bad weather. It is often cloudy or misty and it rains now and again, so the

people don't get much sunshine in the year.     

     When the Chinese student arrived at London Airport, a tall English policeman with a long face checked

his passport. The policeman was interested to find the Chinese name "Sun" in the passport. He thought it

was pronounced just like the English word "sun", so he said to the Chinese student, "I see your name is

Sun. You are wanted here."

     What a surprise to hear that! Everybody knows if you are wanted by the police, you must have

broken the law. So he asked the policeman: "Is there anything wrong with my passport? Do I have to go

back to China right now?" "Go back?" shouted the policeman, "Now you are here, we'll never let you go

away." "What's happened? What have I done?" asked the Chinese student in surprise. He thought he was

going to be arrested.

     It was only then that the policeman began to smile.

     He said, "You don't know what you have done, Mr. Sun? You've brought sunshine to England. So

we don't want you to go away."

1. Where did the story take place?  [ ]

A. At a railway station.

B. At an airport.

C. In a school.

D. At a police station.

2. Mr. Sun was surprised because _____. [ ]

A. the police man took away his passport

B. there was something wrong with his passport

C. the police man was not happy

D. the police man asked him to come to him

3. From the passage we know that _____. [ ]

A. the weather was not fine in England all year round

B. the Chinese students aren't popular in England

C. the policeman was interested in Chinese name

D. Mr. Sun doesn't learn English well

4. The word "arrested" in the passage means _____. [ ]

A. 拘捕

B. 休息

C. 介绍

D. 通知

5. What will be the possible end of the story? [ ]

A. Mr. Sun lives in England for ever.

B. Mr. Sun was taken to the police station.

C. The police man said good-bye to Mr. Sun with a smile.

D. Mr. Sun and policeman will understand each other better.

单项选择题