问题 填空题

为迎接2008年北京奥运会,从东直门到首都机场T3航站楼,修建了一条轨道交通线,全长27.3km,设计运行时间为16min,这条轨道交通线是目前全国最快的地铁线路(如图所示).在设计这条轨道交通线的过程中,科技人员需要进行一些测试.某次测试中列车在平直轨道上由静止开始到最大速度v所用时间为t,设在运动过程中列车所受牵引力和列车所受的阻力均不变,则列车的加速度大小为______;在此段时间t内列车通过的路程为______.

答案

根据匀变速直线运动的速度时间公式得,a=

v
t

这段时间内的平均速度

.
v
=
v+0
2
=
v
2
,则t时间内通过的路程s=
.
v
t=
vt
2

故答案为:

v
t
vt
2

阅读理解

阅读理解。

     Once upon a time there was a writer living by the sea. He had a habit of walking along the

beach before he began his work.

     One day he was walking along the beach, and he saw someone moving like a dancer. He

smiled and began to walk faster toward the men. As he got closer, he saw that it was a young

man and the young man wasn't dancing. He was bending down to the send, picking something

up and very gently throwing it into the.sea.

     As he got closer, the writer called out: "Good morning! What are you doing?"

     The young man stopped, looked up, and said: "Throwing starfish( 海星) into the sea. "

     "Why are you doing that?"

     "The sun is up, and the tide( 潮汐)is going out. And if I don't throw them into the sea, they

will die."

     "But, young man, don't you think that there are so long a beach here, and starfish all on the

beach? You can't make difference. "

     The young man listened politely then bent down, picked up another starfish, threw it into the

sea and said: "It made a difference for that one."

     Each of us can make a difference in this world. Everybody is useful. Every small thing you do

will help. 

1. At first the writer thought the young man _____. 

A. was walking with a dancer

B. was dancing along the beach

C. was swimming in the sea 

2. What was the young man actually doing?  

A. He was watching the sun going up.

B. He was waiting for the tide to go out.

C. He was throwing the starfish into the sea.   

3. What did the young man do after the writer said: "You can't make a difference"?  

A. He was angry.

B. He listened politely without saying anything.

C. He went on doing what he thought was right.  

4. The starfish won't _____ if the young man didn't throw them into the sea.  

A. die

B. live on

C. jumps  

5. What does the story tell us?  

A. Walking along the beach is good for health.

B. Don't stop doing good even if it is a small thing.

C. Give up when others ask you to stop.

问答题 简答题