已知地球半径为R,地球表面重力加速度为g,不考虑地球自转的影响。 (1)推导第一

题型:计算题

问题:

已知地球半径为R,地球表面重力加速度为g,不考虑地球自转的影响。

(1)推导第一宇宙速度v1的表达式;

(2)若卫星绕地球做匀速圆周运动,运行轨道距离地面高度为h,求卫星的运行周期T。

考点:人造地球卫星宇宙速度
题型:计算题

阅读理解。

    At school many things happen to us. We may feel excited when we have success in a school play. We

may feel sorry if we lose an important game. We want to keep the memory for the rest of our lives.

    How to keep the memory? Our English teacher, Miss Wang, has taught us a good way of remembering

things to make our own yearbook. What is a yearbook? A yearbook is a kind of book which is used to keep

the memory of exciting moments. It's usually made at the end of the year.

    Last December, we began to make our yearbook. First we chose the persons who had done something

special, then some students interviewed (采访) them, some wrote down their stories, others took photos

of them. Everyone in our class had something to do. Finally our teacher helped us to put the things together.

We had our first yearbook.

    All of us put a lot of love into making the yearbook. It is so wonderful that not only the students but also

our parents and teachers will remember the special time for ever.

1. When we have success in a school play, we may feel ______. [ ]

A. sorry

B. angry

C. excited

D. interested

2. Miss Wang's good way of remembering things is to ______. [ ]

A. buy a new book

B. write down stories

C. take a lot of photos

D. make a yearbook

3. A yearbook is made to ______.[ ]

A. take notes

B. keep the memory

C. do our homework

D. remember English words

4. Usually a yearbook is made in ______.[ ]

A. January

B. February

C. May

D. December

5. We made our first yearbook ______. [ ]

A. without any help

B. without putting our love into it

C. with the help of our teacher

D. with the help of our parents

题型:计算题

捉呈(外源性)抗原的细胞是

A.NK细胞
B.B细胞
C.肥大细胞
D.细胞毒性T淋巴细胞
E.浆细胞

题型:计算题

入睡则汗出,醒后则汗止()。

A.盗汗

B.自汗

C.战汗

D.大汗

E.绝汗

题型:计算题

下列选项中正确的是

A.赫尔巴特是西方历史上第一位把心理学作为一门独立学科加以研究,并努力建设使之成为一门科学的思想家

B.赫尔巴特将道德教育的目的分为内在目的和外在目的

C.赫尔巴特确定教育过程的顺序是管理、道德教育和教学

D.赫尔巴特提出教学的最根本的目的是要求学生牢固掌握知识和激发学生企图扩充知识的兴趣

题型:计算题

人民群众对历史的创造作用总是受到社会历史条件的制约,其根本的条件是( )。

A.生产力和生产关系的状况
B.人们头脑中的传统观念
C.科学文化水平
D.人们的生活水平

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