问题 选择题

下列关于惯性的说法中正确的是(      )

A.物体只有静止或做匀速直线运动时才有惯性

B.物体只有受外力作用时才有惯性

C.物体运动速度大时惯性大

D.一切物体都有惯性

答案

答案:D

题目分析:惯性是物体的一种属性,只与物体的质量有关,与物体的受力和运动状态无关,一切物体均有质量,所以一切物体均有惯性。

故选D

点评:有的同学总认为:“惯性与物体的运动速度有关,速度大惯性就大,速度小惯性就小”,理由是物体运动速度大不容易停下来,速度小容易停下来.产生这种错误认识的原因是“把惯性大小理解为把物体从运动改变为静止的难易程度”.事实上,在受到相同阻力的情况下,速度不同质量相同的物体,在相同的时间内速度的减小量是相同的,这就说明质量相同的物体,它们改变运动状态的难易程度惯性是相同的,与它们的速度无关.

完形填空

阅读下面短文并回答问题,然后将答案写到答题卡相应的位置上(请注意问题后的词数要求)。

[1] Doctors say anger can be an extremely damaging, unless you learn how to deal with it.They warn that anger can lead to heart disease, stomach problems, headaches, emotional problems and possibly cancer.

[2] Anger is a normal emotion that we all feel from time to time, some people express anger openly in a calm reasonable way.Others burst with anger, and scream and yell.But other people keep their anger inside.They can not or will not express it.This is called ______________.

[3] For years many doctors thought that repressing anger was more dangerous to a person’s health than expressing it.They said that when a person is angry, the brain release the same hormones.They speed the heart rate, raise blood pressure, or sugar into the blood, etc.In general the person feels excited and ready to act.

[4] Some doctors say that both repressing and expressing anger can be dangerous.They believe that those who express anger violently may be likely to develop heart disease, and they believe that those who keep their anger inside may face a greater danger of high blood pressure.

[5] Doctors say the solution is learning how to deal with anger.They say the first step is to admit that you are angry and to recognize the real cause of the anger, then decide if the cause is serious enough to get angry about.If it is, they say, “Do not express your anger while angry.Wait until your anger has cooled down and you are able to express yourself calmly and reasonably.”

[6] Doctors say that a good way to deal with anger is to find humor in the situation that has made you angry.They said that laughter is much healthier than anger.

小题1:What is the best title of the passage? (no more than 8 words.)

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小题2:What does the word “it ” ( Line 3 Para 2 ) refer to? ( no more than 2 words )

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小题3:Please fill in the blank with proper words or phrases to complete the sentence.(no more than 3 words)

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小题4:List the three ways the author mentions people express their anger.(no more than 20 words)__________________________________________________________________________________

小题5:According to the doctors, what good way can you get to deal with anger? (no more than 5 words)

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判断题