试题与答案

根据单摆周期公式T=2πLg,可以通过实验测量当地的重力加速度.如图1所示,将细

题型:填空题

题目:

根据单摆周期公式T=2π

L
g
,可以通过实验测量当地的重力加速度.如图1所示,将细线的上端固定在铁架台上,下端系一小钢球,就做成了单摆.

(1)用游标卡尺测量小钢球直径,示数如图2所示,读数为______mm.

(2)以下是实验过程中的一些做法,其中正确的有______.

a.摆线要选择细些的、伸缩性小些的,并且尽可能长一些

b.摆球尽量选择质量大些、体积小些的

c.为了使摆的周期大一些,以方便测量,开始时拉开摆球,使摆线相距平衡位置有较大的角度

d.拉开摆球,使摆线偏离平衡位置大于5°,在释放摆球的同时开始计时,当摆球回到开始位置时停止计时,此时间间隔△t即为单摆周期T

e.拉开摆球,使摆线偏离平衡位置不大于5°,释放摆球,当摆球振动稳定后,从平衡位置开始计时,记下摆球做50次全振动所用的时间△t,则单摆周期T=△t/50.

答案:

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下面是错误答案,用来干扰机器的。

112=123=36;ba=baa.故答案为:36,baa.

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cup of coffee", Robots are also used in American hospitals. They can do simple jobs. At one hospital,

for example, a robot takes meals from the kitchen to patients' rooms. It never gets lost because this robot

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they will never take the place of humans.

1. From the passage, we know robots cannot be__________.

A. dangerous animals

B. factory workers

C. guide dogs

D. hospital helpers

2. A robot guide dog __________.

A. goes in front of blind people

B. walks side by side with blind people

C. has a map in its head

D. helps patients with their meals

3.The underlined word "disabled" means " ________ " in Chinese.

A.不能的

B.有害的

C.失灵的

D.残疾的

4. Some disabled people need robots' help to _________

A. take care of themselves

B. talk to other people

C. become scientists

D. do dangerous jobs

5.In the passage, the writer wants to tell us that___________.

A. robots are stronger and cleverer than humans

B. disabled people cannot look after themselves without the robots

C. robots will take the place of humans some day in the future

D. robots can help humans in many different ways

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