题干

手握如图所示的两张纸,让纸自由下垂,在两张纸的中间向下吹气,你将看到什么现象?此现象能说明什么物理知识?请举出日常生活中应用此物理知识的一个实例

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答案(点此获取答案解析)

答:当向中吹气时,中间的空气流动的速度增大,压强减小,纸外的压强不变,纸受到向内的压强大于向外的压强,受到向内的压力大于向外的压力,受到纸在压力差的作用下向中间靠拢,此现象说明气体流速大的地方压强越小。在生产、生丟中,喷雾器就是应用这个原理工作的。

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Evaluating Sources (来源) of health Information

    Making good choices about your own health requires reasonable evaluation. A key first step in bettering your evaluation ability is to look carefully at your sources of healthy information. Reasonable evaluation includes knowing where and how to find relevant information, how to separate fact from opinions, how to recognize poor reasoning, and how to analyze information and the reliability of sources. ____

    Go to the original source. Media reports often simplify the results of medical research. Find out for yourself what a study really reported, and determine whether it was based on good science. Think about the type of study. ____

    Watch for misleading language. Some studies will find that a behavior "contributes to" or is "associated with" an outcome; this does not mean that a certain course must lead to a certain result. ____ Carefully read or listen to information in order to fully understand it.

    Use your common sense. If a report seems too good to be true, probably it is. Be especially careful of information contained in advertisements. ____ Evaluate "scientific" statements carefully, and be aware of quackery(江湖骗术).

    ____ Friends and family members can be a great source of ideas and inspiration, but each of us needs to find a healthy lifestyle that works for us.

    Developing the ability to evaluate reasonably and independently about the health problems will serve you well throughout your life.

A. Make choices that are right for you.

B. The goal of an ad is to sell you something.

C. Be sure to work through the critical questions.

D. And examine the findings of the original research.

E. Distinguish between research reports and public health advice.

F. Be aware that information may also be incorrectly explained by an author's point of view.

G. The following suggestions can help you sort through the health information you receive from common sources.