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问题 实验题

如图所示，是探究“摩擦阻力对物体运动的影响”的实验：

（1）每次实验，小车都是从同一高度下滑，这是为了使小车在不同的水平桌面上开始运动时具有相同的        。

（2）由于摩擦阻力的大小与             有关，所以小车在不同表面上运动的距离不等，表面越光滑，小车受到的阻力越           （选填“大”或“小”），小车运动得越        （选填“远”或“近”）．由此我们进一步推理，若小车受到的摩擦阻力为零，小车将                                  。

（3）上述实验中，若小车上放入钩码，则小车从光滑斜面的同一高度滑下，则达到水平面时的速度将        ，小车在水平面上的距离将         。（选填“增大”、“不变”或“减小”）

答案

（1）速度       （2）接触面的粗糙程度；小；远；匀速直线运动　（3）不变；减小

题目分析：（1）小车从斜面滑下的高度不同，到底端时的速度就不同，所以让小车从同一高度由静止滑下的目的是使小车在水平面上的初速度相同；

（2）摩擦力大小与压力大小和接触面的粗糙程度有关，当压力一定时，摩擦力大小就受粗超程度的影响：接触面越光滑，小车受到的阻力越小，小车运动得越远，进一步推理：如果小车不受阻力，将永远做匀速直线运动；

（3）小车到达斜面底端的速度只和小车开始由静止下滑的高度有关，与质量无关，所以放入钩码后，到达水平面时的速度不变，在平面上运动时，由于压力增大，所以摩擦力增大，小车运动的距离将变小。

填空题

根据所给的首字母填写单词。

     There are some very good things about open education. This way of teaching a      l      the students to develop their interests in many subjects. Open education asks students to be responsible(负责任)for their own education. The open classroom may help them to e      2     learning. Some students will be h    3    in an open education school. They will not have to worry a    4     grades rules.

     But many students may not d      5      well in an open classroom.  For some students,  if there are too f     6      rules, they will do little in school. They will not make good use of open education. Because open education is s    7      different from traditional education, these students may have a problem of getting used to making so many c    8    .For many students it is important to have some rules in the classroom. A few rules will help them.  The  last point  about  open  education is that some traditional teachers  do not like it.

Many teachers do not believe in open education.

     You now know what open education is. Some of its good points and bad points have been explained. You may have your own opinion about open education. The writer thinks that open education is only a

good idea. It may not work very well in r    9    class or school. The writer believes that most students, but of course not all students, want and need to have some rules. They must be m  10  to study some subjects. Many students are pleased to find subjects that they have to study interesting. They would not study those subjects if they did not have to.

1. a________ 2. e________ 3. h________ 4. a_______ 5. d_______

6. f________ 7. s________ 8. c________ 9. r_______ 10. m_______
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多项选择题

预应力孔道灌浆用水泥浆及灌浆质量检查应包括下列内容：（）。

A.水泥浆的稠度

B.水泥浆的泌水率

C.水泥浆的膨胀率

D.灌浆记录

E.水泥浆试块强度
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