问题 单项选择题

伽利略用两个对接的斜面,一个斜面固定,让小球从固定斜面上滚下,又滚上另一个倾角可以改变的斜面,斜面倾角逐渐改变至零,如图所示.伽利略设计这个实验的目的是为了说明()

A.如果没有摩擦,小球将运动到与释放时相同的高度

B.如果没有摩擦,物体运动时机械能守恒

C.维持物体做匀速直线运动并不需要力

D.如果物体不受到力,就不会运动

答案

参考答案:C

解析:

伽利略的理想斜面实验证明了:运动不需力来维持,物体不受外力作用时,总保持原来的匀速直线运动状态或静止状态,故ABD错误,C正确。

完形填空

阅读下面的短文,根据短文内容及首字母提示,在短文空白处填入一个恰当的词,使短文内容完整、通顺,将所填单词填写在答题卡上相应的题号后。

Young people are the future masters of the country. Being a youth is one thing, and being a good one is a_______小题1:. Everyone tries to be good, but not e_________小题2: has the right idea about it. Age will test youth, and youth will create age. Because we’ll have heavy responsibilities(责任) upon our shoulders in future. We must educate ourselves to be good. What are the qualifications(素质) for a good young person?

A good youth should have these qualities: F________小题3:of all, health, a healthy body is the best riches. W__________小题4: it, nothing can be done well. If you are poor in health, you’ll have to take m_______小题5:day after day. Even you can’t work, do sports and so on; Secondly, one must be of good quality. Always do something for others. Help those in t__________小题6: and care about the people around you. If everyone did the same, what a wonderful world this w________小题7: be! Thirdly, one must have the ability to work with others.

Cooperation(合作) and communication are two important keys to better human relations. Everyone n__________小题8:friends because no one can live through life alone or do everything he wants to.

Besides the examples above, patriotism(爱国主义) is the one we should never forget. Patriotism means a love of one’s country. It is one of the h__________小题9: qualities of humans. Everyone should love his o_______小题10: country.

I think a good youth of today should also have some training in art. If everyone can enjoy art and be able to make more of it for others, then people will live b________小题11: and enjoy more.

单项选择题