问题 问答题

雷达应用非常广泛,在交通上可以用来为飞机、轮船导航;在宇宙探索中可用来研究星体,在气象上可以用来探测台风,雷雨、云层等;特别是在军事上应用更广泛.我国沿海某雷达站,发现一架不明国籍的飞机正向我国领空飞来,雷达发出无线电波,经过2.00×10上标-4 s,接收到从飞机反射回来的无线电波,10 s后,该雷达站又发出无线电波,经过1.86×10上标-4 s接收到从飞机反射回来的无线电波,试确定该飞机的飞行速度为多少?

答案

176 m/s

利用雷达发射和接收无线电波的时间差可以计算出飞机这段时间中间时刻与雷达的距离.

飞机的速度

v=

=m/s≈176 m/s.

阅读理解

阅读理解 (共15小题;每小题2分,满分30分)

阅读下面短文,从每题所给的A、B、C、D四个选项中,选出最佳选项

Daily Horoscope(占星)on May 5th

Aries:Everything is getting ready. You are in the right place at the right time. Cheer up and catch good chances.

Taurus:If something isn’t what you think, don’t worry. Wait patiently and you will have a better chance. But a mistake now will bring you trouble.

Gemini:Your experience and ability will attract others’ attention today. You’ll be asked for your opinions, and you will be able to get everything you want.

Cancer:Put on a big push and you will make some extra money. This is a great day to go for interviews or talk to someone about your ideas.

Leo : You’ll have success at work but don’t spend too much money. A short trip will bring good results.

Virgo:If you don’t know enough about something, keep away from it. Think before you take actions. Be honest, or you’ll be in trouble.

Libra : Joining a good group will make you catch a chance. Then you can get what you want.

Capricorn :Don’t believe anyone who pretends(假装) to know everything. Do everything on your own.

Aquarius:Try your best to help others and you’ll attract everyone’s attention. Friendship is the most important thing to you.

Pisces:You may meet someone who will invite you to a talk or a meeting. Be careful enough or you’ll make enemies.

小题1:Who has the best luck on May 5th?

A.A Gemini.

B.A Virgo.

C.A Leo.

D.A Pisces.小题2:The underlined part “put on a big push” means "______ " in Chinese.

A.用力推一下

B.用力拉一下

C.穿件大衣服

D.奋力拼搏一下小题3:Who needn’t pay attention to others but depend on(取决于)himself ?

A.A Libra.

B.A Cancer.

C.An Aquarius.

D.A Capricorn.

选择题