问题 实验题

(1)(8分)实验室利用打点计时器研究小滑块的运动情况,打出如图所示的纸带,其中纸带B端与滑块相连接,计时器接在频率为50Hz的交流电源上。请回答下列问题:

①纸带中AB段运动的时间为______________.

②根据纸带请判断该滑块的运动属于_______(填“匀速”、“匀加速”、“匀减速”)直线运动.

③从纸带可以测出AB两点间的距离为____________,滑块的加速度大小为___________(计算结果保留三位有效数字).

(2)(10分)为了测量某一未知阻值的电阻Rx,某实验小组找来以下器材:电压表(0~3V,内阻约3kΩ)、电流表(0~0.6A,内阻约1Ω)、滑动变阻器(0~15Ω,2A)、电源(E=3V,内阻很小)、开关与导线,该小组同学实验操作如下,请你按要求填写:

①断开开关,请按图甲所示的电路图在图乙中连接实物图;

②如图乙,闭合开关前,应将滑动变阻器的滑片置于_______端。

③闭合开关,缓慢调节滑动变阻器,得到多组电压表与电流表的读数,建立合适的坐标系作出I-U图如下;

④整理仪器

根据I-U图可得,该未知电阻的阻值为Rx=______。(保留两位有效数字)

由于实验中使用的电表不是理想电表,会对实验结果造成一定的影响,则该小组同学实验测出的电阻值_____________ RX的真实值(填“>”、“<”或“=”)。

利用现有的仪器,为了更加精确地测量这个电阻的阻值,你给该实验小组的建议是:

                

答案

(1)(8分) 0.08s 匀加速  9.20cm  5.00m/s2 

每空2分 不给单位的不给分

(2)(10分)连线如图        (2分)

a(“左”也正确)(2分)

Rx=5.0Ω。(4.8Ω~5.0Ω均正确)(2分)

>          (2分)

电流表外接   (2分)

(1)频率,所以周期0.02s。所以:纸带中AB段运动的时间为:

从纸带的图像上可以看出每两个点的距离越来越大,所以做匀加速直线运动。从纸带可以测

出AB两点间的距离为:10.2-1=9.2m。加速度

阅读理解

Look at the center circles of Diagram (图) A and Diagram B.  Which of the centre circles looks larger? 

Take a first look and you probably think that the centre circle in Diagram A is smaller than that in Diagram B. In fact , they are exactly the same size.

Then look at the picture on the right. What do you see? A vase ? Or two faces? Does the picture change quickly from one to the other again and again? Maybe or maybe not, but you can never see them at the same time. 

"What's happening? Is something wrong with my eyes?" You may wonder at what you see. Don't worry. Here is how it goes:

When we look at things, our eyes send messages to our brains and then our brains interpret (解读) the information. However, sometimes our brains interpret the received information in a wrong way. It seems that our eyes are playing a joke on us. This often happens and we call it "Visual illusion" (视觉错误). 

Movie makers often make use of illusions. They make the objects around actors much smaller or bigger than usual. This makes us believe that the actors are much larger or smaller than they usually are. The movies Jurassic Park and Honey I shrunk the kids just make use of illusions.

小题1:The centre circle in Diagram A looks smaller than that in Diagram B. That's because           .

A. something is wrong with our eyes

B. the two circles are not the same size

C. our brains interpret the information in a wrong way

D. the two pictures change quickly from one to the other

小题2:What's the right order according to the passage?

a. We look at things with our eyes.              b. Our brains interpret the messages.

c. Our brains tell us what we have seen.      d. Our eyes send messages to our brains.

A.adbc

B.cabd

C.acdb

D.bcad小题3:Movie makers make use of visual illusions to            .

A.help the actors look better

B.make the actors much braver

C.help the actors become stronger

D.make the actors seem different in size小题4:In the picture on the right, it seems that Line AB is shorter than Line CD, but in fact Line AB is as long as Line CD. Which paragraph can explain what has happened to our eyes?___________

   

A.The second one.

B.The third one.

C.The fifth one.

D.The sixth one.

小题5:The text is probably taken from            .

A.an advertisement

B.a science book

C.a movie magazine

D.a story book

单项选择题