问题 实验题

(9分)取两张等大的圆形纸,分别剪去两个大小不等的扇形(图甲所示),再将它们做成图乙所示的两个锥角不等的纸锥。

(1)为了比较纸锥下落的快慢,可将纸锥按如图乙     (选填“A”或“B”)所示的位置释放。若纸锥从同一高度同时由静止释放,可通过比较下落至地面的       来比较纸锥下落的快慢; 还可以比较同一时刻纸锥下落的                  来比较下落的快慢。其中第      种比较方法与物理学中速度的定义方法相接近。

(2)如果要测量两个纸锥的下落速度,需要的测量工具有                 

(3)在测量过程中,发现________(选填“下落的时间”或“下落的路程”)较难测出,于是我们可采用增加____________或换用锥角较________(选填“大”或“小”)的纸锥进行实验。

答案

(1)A;时间;路程;2;(2)刻度尺;秒表;(3)下落的时间;下落高度;大

题目分析:(1)要比较纸锥下落的快慢,应让它们的下端相平,因为下落到地面是尖端触地;比较快慢,可以采取通过相同的路程比时间的方法,也可以用运动相同的时间比路程的方法;物理学中,我们把运动物体在单位时间内通过的路程叫速度,实际是采取的相同时间比路程的方法;

(2)测量速度时,要用刻度尺测出物体运动的路程,用秒表测出运动这段路程所需的时间,再用公式计算;

(3)由于纸锥下落较快,所以时间太短,不易测量,增加纸锤下落的高度,可使下落时间变长,或增大纸锥的锥角,使它下落时受到的空气阻力增大,下落速度变慢,时间变长。

阅读理解

When I was learning calligraphy my teacher told me a story.

A calligrapher taught handwriting. One of his students who often practised handwriting with old sheets of newspapers complained that he made very little progress though he had learned it with the calligrapher for a long time. His teacher said to him, “Try to use the best paper. Maybe you’ll write better. ”

 The student did as he was told. It really worked. He made headway not long afterwards and felt curious. He asked his teacher about the reason. The calligrapher answered, “When you used old newspapers to practice handwriting,you would think you were writing a draft(草稿).  It didn’t matter if you wrote badly as old newspapers were plenty in supply. In that case you wouldn’t pay much attention to it. Now you use the best paper you’ll treasure it. Each time you write you feel strongly about the rarity (稀少) of chances and you’ll devote to it with all your heart and soul; you’ll do the handwriting much more attentively than otherwise practising it. Of course you’ve made rapid progress.”

Indeed,we spend our ordinary days just as they are worthless “old newspapers”. We don’t care if we scrawl and waste them, thinking that they will come endlessly --- those “old newspapers” are inexhaustible. In such a mood we may each day pass by opportunities but fail to catch any of them.

Life is not a military exercise but an actual war in which real weapons are used. In everyday life there’s no chance for us to draw a draft. That’s because what we call “draft” actually is the answer sheet we write that cannot be changed. Every day of our life is something new. Let us take every day as a sheet of best paper.

小题1:The calligrapher in the story told the student to write on the best paper because he thought _______.

A.the student would practice more carefully on the best paper

B.it was comfortable to write on the bet paper

C.the student had enough money to buy the best paper.

D.the student could write more on the best paper.小题2:The student didn’t make much progress at first because _________.

A.he regarded his writing on old newspaper just as a draft

B.he was too poor to buy better paper to write

C.he didn’t follow his teacher’s advice

D.he was not used to the calligrapher’s teaching manner小题3:We learn from the passage that _________.

A.the student finally gave up

B.the student made rapid progress by persisting more carefully

C.the calligrapher was strict with his students

D.old newspaper is not useful小题4:Which of the following is true according to the passage?

A.What teachers say is always true.

B.Success calls for attentiveness.

C.Handwriting is easy to practice.

D.New things are always better than old ones.小题5:The writer wants to tell us that _________.

A.there are some good ways to practice handwriting

B.life is like old newspaper

C.we should learn from the student in the story

D.life will not give us a chance to draw a draft

单项选择题