问题 不定项选择

组成星球的物质是靠引力吸引在一起的,这样的星球有一个最大的自转速率,如果超过了该速率,星球的万有引力将不足以维持其赤道附近的物体做圆周运动。由此能得到半径为R、密度为ρ、质量为M且均匀分布的星球的最小自转周期T。下列表达式中正确的是[ ]

A.T=2π

B.T=2π

C.T=

D.T=2

答案

答案:A

阅读理解

阅读理解

     Nuclearpowered aircraft carriers are considered one of the most important marine weapons in the

20th century. So far, only two countries in the world, the USA and France, have ever produced them.

But these fearful fighting machines are about to enter Asia.

    The US Navy said last month that one of its nine nuclearpowered aircraft carriers will be sent to

Japan to replace the diesel(柴油)powered carrier Kitty Hawk in 2008. In an agreement on October

30, the two countries also planned to level up their military (军事的) cooperation and the USA called

for Japan to take a larger role in alliance military moves.

     It will be the first time that a nuclearpowered carrier is based in Japan. Bombed by US forces in

World War ? at Hiroshima and Nagasaki, Japan is the only world country to have been attacked by a

nuclear weapon. Therefore, the citizens are highly sensitive to where nuclearpowered weapons are

based.

      "A radiation leak at Yokosuka would kill 100,000 people as far away as Tokyo, and could cause

billions of dollars in damage," said Masahiko Goto, leader of a protest group in Yokosuka. His group

has collected more than 300,000 signatures of people across Japan opposed to the nuclear carrier.

     The 44yearold Kitty Hawk, the US Navy's oldest active ship, has been based in Yokosuka since

1998. It had returned to the US to be decommissioned in 2008. The new carrier, yet to be unveiled,_

will travel faster, be capable of supporting longer operations and carry with it the Navy's most modern

technology.

     Experts pointed that this change is not only to strengthen the USJapan military alliance but also to

keep the military power of China and North Korea within limits. However, even Japanese experts don't

believe that the two countries are threats to the region.

     "There is no need for Japan to have a nuclear carrier as defense," said Tetsuo Maeda, an international

relations professor at Tokyo International University. He said that the change of ship indicates an

increased military capability in the region, much more than what is needed.

1. With such a formidable weapon to enter its country, Japanese citizens ________.

A. are aware of its benefits to the country

B. are anxious about its potential danger

C. are curious about the advanced technology

D. are against where the carrier will be based

2.The underlined word "unveiled" in the fifth paragraph probably means________.

A. perfected  

B. discussed about

C. produced  

D. brought to view

3. By his remark in the last paragraph, the professor means that________.

A. he is quite confident of their military defense

B. he is completely opposed to a new nuclear carrier

C. what is needed is far more than a nuclear carrier

D. it is unnecessary to guard against the two countries

填空题