问题 选择题

作匀加速直线运动的列车出站时,车头经过站台时的速度为1m/s,车尾经过站台的速度为7m/s,则车身的中部经过站台的速度为(   ) 

A.3.5m/s

B.4.0m/s

C.5m/s

D.5.5m/s

答案

答案:C

题目分析:根据匀变速直线运动的规律,中间位移的瞬时速度为,代入数据可得:车身的中部经过站台的速度为5m/s,所以C正确;A、B、D错误。

阅读理解

阅读理解。

     It was a quiet village in which there was a military camp(军营).It was far from the towns and cities

and there were some high mountains around. Of course it was a good place for training the new soldiers.

But it was difficult for the young men to go outside. Mr White, an officer of forty, was strict with them

and he hardly let them leave the camp.

     Once Mr White was ill in bed. He couldn't work and a young officer, Mr Hunt began to train the new

soldiers instead of him. He knew the young men well and let nine soldiers go to the nearest town to have

a holiday. But night fell and none came back to the camp. He was worried about it and stood at the gate.

It was five to twelve when Mr Hunt decided to go to the town and see what was happening to the young

men.He started the car quickly and set off. At that moment the nine soldiers came back. It seemed they

drank wine. Of course they found the officer was angry.

     "I'm sorry, sir," said the first soldier. "I left the town on time. But something was wrong with my bus on my way here. I had to buy a horse and made it run fast. Bad luck! It died and I had to run back."

     And the other seven soldiers said they were late for the same reasons. It was the last soldier's turn. He said, "I'm sorry, sir. I got on a bus on time, but…"

     Having heard this, the officer became even angrier and stopped him at once. He called out, "If you say something was wrong with your bus, I'll punish you at once!"

     "No, no, sir," said the young man. "My bus was all right, but the horse died!"

1. The military camp was built in the village to     __.

A. stop the soldiers from going to towns

B. stop the soldiers from meeting their friends

C. train the new soldiers              

D. make the young men live quietly

2. Mr Hunt let the nine soldiers have a holiday because      __.

A. he was kind to them                

B. they felt lonely

C. they had something important to do    

D. they were the best of all

3. The young officer was worried because     __ .

A. a traffic accident had happened

B. he was afraid something happened to the nine soldiers

C. the nine soldiers would come back  

D. the nine soldiers drank too much in the town

4. The nine soldiers returned to the camp late because       __.

A. something was wrong with their buses    

B. their horses died on the return way

C. it took them much time to run back      

D. they all drank much in the town

5. Which answer do you think is true?

A. You'll believe only the last soldier.      

B. The officer believed the nine soldiers.

C. You'll believe none of the nine soldiers.  

D. The officer won't punish his soldiers.

单项选择题