问题 问答题

学习了简单机械后,小明了解到斜面也是一种机械,想探究这种机械的特点.

(1)小明用弹簧测力计测木块的重力,如图(a)所示,测量时应让木块保持 ______状态,并依据 ______条件得出木块重力的大小等于弹簧测力计的示数;

(2)他将木块放在如图(b)所示的斜面上,并用弹簧测力计沿斜面匀速上拉木块,收集到下表中的实验数据:

斜面倾斜程度木块重力G/N斜面高度h/m斜面长S/m沿斜面拉力F/N
 较缓 5 0.2 1 2
 较陡 5 0.3 1 2.6
 最陡 5 0.4 1 3.2
①比较表中木块重力G和拉力F的大小,得出:使用斜面时 ______(选填“能”或“不能”)省力;

②实验时,可以通过移动木块A来改变斜面的倾斜程度,要减小斜面的倾斜程度,木块A要向 ______移(选填“左”或“右”);

③请举出斜面的一种应用实例:______;

④生活中有哪些可以省力的机械:______(写出一种即可).

答案

(1)物体静止时,根据二力平衡条件可知,弹簧测力计的示数就是物体的重力.

(2)由数据可以看出使用斜面省力,由图可以看出木块向右移动,斜面倾斜角度减小,斜面的原理应用到盘山公路等,省力的机械有动滑轮等.

故答案为静止;二力平衡;能;右;盘山公路;动滑轮.

阅读理解

Ann Whimey, a sophomore(大学二年级学生) at Colorado State University, first had a problem taking tests when she began college. "I was always well prepared for my tests. Sometimes I studied for weeks before a test. Yet I would go to take the test, only to find I could not answer the questions correctly. I would blank out because of nervousness and fear. I couldn't think of the answer."

The young student was experiencing something called test anxiety. Because a student worries and is uneasy about a test, his or her mind does not work as well as it usually does. The student cannot write or think clearly because of the great nervousness. though poor scores are often a result of poor study habits, sometimes test anxiety causes low scores. Recently, test anxiety has been recognized as a real problem, not just an excuse or a false explanation of lazy students.

Special university counseling(咨询) courses try to help students. In these courses, counselors try to help students by teaching them how to manage test anxiety. At some universities, students take tests to measure their anxiety. If the test shows their anxiety is high, the students can take courses to help them deal with their nervousness. These courses teach students how to relax their bodies. By controlling their nervousness, they can let their minds work at ease, learn information, then come out without difficulty in a test.

An expert at the University of California explains, "With almost all students, relaxation is felt after taking our program. Most of them have better control during their test. Almost all have some improvements. For some, the improvement is very great.

小题1:The title of the passage should be                        

A.Tests at college

B.Anxiety and Tests

C.How to Get Rid of Anxiety

D.Counseling Courses Help Students小题2:According to this passage, we mainly find poor scores may result from     

A.laziness

B.sleeplessness

C.nervousness

D.poor study habits小题3:In order to get rid of test anxiety, students should  

A.take tests to measure their anxiety

B.take counseling courses to help themselves

C.let their minds work at ease

D.learn to control their nervousness小题4:According to the counselor at the University of California, the program is    

A.successful

B.ineffective

C.of great help to all

D.worth showing off

问答题 简答题