问题 问答题

一列长为l=1500m的货运列车,在平直的轨道上匀速行驶,运动中所受阻力为f=4×105N.在要通过某长度为L=600m的跨江大桥时,为提醒大桥上铁轨两旁的行人注意,处于车头的司机在机车到达桥头时拉响汽笛,位于车尾的押运员经过t1=4s听到汽笛声,已知空气中声速为v1=340m/s,求:

(1)列车机车提供的牵引力F;

(2)列车的行驶速度v2

(3)列车通过大桥的时间t2

答案
阅读理解

阅读理解。

     Joe Biggs was a butcher (屠夫). His shop was in a village in one of the most beautiful parts of southern

England. He worked in it for many years while his father was there. Then, when his father reached the age

of 65, he stopped working in the shop. Joe was alone in it, so he had to work harder.

     Joe worked five and a half days a week. His shop shut at one o'clock on Thursday, and it was shut the

whole of Sunday. Saturdays were the busiest days.

     Joe had a big fridge in his shop, but he tried not to buy too much meat at a time.

     One Thursday a woman came into the shop at five minutes to one. "I'm sorry I'm very late," she said,

"but some people have just telephoned to say that they are going to come to dinner tonight, and I need some

more meat."

     Joe only had one piece of good meat in the shop. He had sold all the rest earlier in the day. He took the

piece out and said to the woman. "This is £7 15." "That piece is too small," the woman answered. "Haven't

you got anything bigger?"

     Joe went into the room behind his shop, opened the fridge, put the piece of meat into it, took it out again

and shut the door of the fridge with a lot of noise. Then he brought the piece of meat back to the woman and

said, "This piece is bigger and more expensive. It's £9. 30."

     " Good," the woman answered with a smile, "give me both of them, please."

1. Joe worked alone in the shop _____.

A. on Saturdays

B. on Thursdays

C. after his father died

D. after his father stopped working 

2. Joe sold meat in his shop _____.

A. on Thursday afternoons

B. on Sundays

C. on Fridays

D. every day

3. One day a woman came to his shop _____.

A. at 1:55, Tuesday

B. at 1:05

C. to say sorry to him

D. because someone had suddenly telephoned her

4. Joe only had one piece of good meat because _____.

A. Joe's fridge was too small.

B. he tried not to buy too much meat at a time

C. he knew that the meat would go bad (变质)

D. he had no money to buy more

5. Which of the following is TRUE?

A. The woman wanted to buy the two pieces of meat together.

B. The woman didn't want the expensive piece of meat.

C. Joe brought the woman a different piece.

D. People bought all the meat from him.

单项选择题