问题 问答题

为了保卫国家和人民的核心利益,有效对远距离恐怖活动实施精确打击,目前我国正在致力于超音速飞行器的研究,并取得了很大进展,如图是正在研制的某型号超音速飞行器.据报到,我国科学家正计划在位于北京的风洞中测试速度达5.6马赫的高超音速实验飞行器模型.已知声音在空气中的传播速度约为340米/秒,1马赫等于1倍音速.

(1)如果我国5马赫的高超音速飞行器研究成功并投入使用,则它的飞行速度可达到多少米/秒?1小时它能飞行多少千米?

(2)若使用5马赫的高超音速飞行器对5100千米外的恐怖活动实施精确打击,飞行器需要飞行多少分钟?

答案

(1)超音速飞行器飞行的“马赫数”为5.6,故飞机速度:

v=5.6v=5.6×340m/s=1904m/s=1904×3.6km/h=6854.4km/h;

超音速飞行器1小时飞行的路程:

s=vt=684.4km/h×1h=6854.4km;

(2)若超音速飞行器飞行的“马赫数”为5时,飞行速度:

v′=5v=5×340m/s=1700m/s;

飞行5100千米需要时间:

t′=

s′
v′
=
5100×1000m
1700s
=3000s=3000×
1
60
min
=50min

答:(1)它的飞行速度可达到1904米/秒?1小时它能飞行6854.4千米;

(2)飞行器需要飞行50分钟.

阅读理解

阅读理解。

     A few months ago my father and I visited Singapore, one of the most beautiful cities in Asia.

     The city of Singapore is (1)f_______ for its business (商业) and other activities. There are many

places of interest such as the Tiger Balm Garden and Raffles Museum. There are also many important

centers of (2)l_______ such as the University (大学) of Singapore and the Science Centre. Being a

famous city, hundreds of people do business or go(3)s_______. Most tourists like the sights of the

city.

     During my stay in Singapore, I went out every day with my father to see the beautiful and interesting

places and things in the city. One day we went to the Tiger Balm Garden (4)w______ I saw many

animals. We spent about half of the day visiting this place.

     Every night, I went around the city and (5)v_______ some of the parks. I also visited a few of the

cinemas (电影院).

     I enjoyed every moment of my stay in the city of Singapore.

 I. 根据首字母和上下文提示,用单词的适当形式补全短文。

    1. ________2. ________ 3. ________ 4. ________5. ________

    

 II. 根据短文内容,完成下面的表格。  

     Famous places in Singapore Tiger Balm Garden, (6)__________, University of Singapore and

(7)______

     What did the writer do during the day?

     He went out to see the (8)________ places and things.

     What did the writer do during the night?

     He went around the city and went to the (9)________. He also went to some (10)________.

单项选择题