1783年,法国物理学家查理做成的世界第一个可载人气球,体积为620m3.设地面

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问题:

1783年,法国物理学家查理做成的世界第一个可载人气球,体积为620m3.设地面附近空气的密度为1.3kg/m3,则这个气球在地面附近受到空气的浮力为______ N.这种求浮力的方法称为阿基米德原理.那么阿基米德原理的内容是______.

考点:浮力及阿基米德原理
题型:填空题

生殖健康的定义是什么?

题型:填空题

情景对话。

A: Hi I am Wang Hong. I am a journalist from Taiyuan TV Station. I want to know something about

    your school life. Could you 1______ about it?

B: Yes, I'd love to. 

A: Well, 2______

B: About two thousand students in our school. 

A: And are you always busy with your lessons?

B: 3______ We have much homework to do every day. We have to work hard. 

A: What about your free time?

B: We can take part in different kinds of activities. 4______ in our school. And these hobby groups

    are open to us on Friday afternoons.

A: I think your school is wonderful, isn't it?

B: I think so.

A: It's nice talking to you. 5______

B: You're welcome.

题型:填空题

并殖吸虫病应与哪些疾病鉴别()

A.肺结核

B.囊虫病

C.结核性胸膜炎

D.颅内肿瘤

E.霍乱

题型:填空题

阀门按()分类可分为低压阀、中压阀、高压阀和超高压阀。

A.大小

B.作用

C.结构

D.压力

题型:填空题

当峰值温度一定时,为了减少晶粒尺寸,应该尽量较少又800~500℃的冷却时间,也就是尽量限制焊接()。

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