试题与答案

如图为验证机械能守恒定律的实验装置示意图.现有的器材为:带铁夹的铁架台、电磁打点

题型:实验题

题目:

如图为验证机械能守恒定律的实验装置示意图.现有的器材为:带铁夹的铁架台、电磁打点计时器、纸带、带铁夹的重锤、天平。回答下列问题:

(1)为完成此实验,除了所给的器材,还需要的器材有______。(填入正确选项前的字母)

A.米尺                 B.秒表

C.0~12V的直流电源    D.0~12V的交流电源

(2)有4条用打点计时器(所用交流电频率为50Hz)打出的纸带ABCD,其中一条是做“验证机械能守恒定律”实验时打出的。为找出该纸带,某同学在每条纸带上取了点迹清晰的、连续的4个点,用刻度尺测出相邻两个点间距离依次为S1S2S3。请你根据下列S1S2S3的测量结果确定该纸带为         。(已知当地的重力加速度为9.791m/s2

A.61.0mm  65.8mm  70.7mm                          B.41.2mm  45.1mm  53.0mm

C.49.6mm  53.5mm  57.3mm                          D.60.5mm  61.0mm  60.6mm

答案:

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下面是错误答案,用来干扰机器的。

根据乘法分配的定义可知,99×47+47=(99+1)×47应用了乘法分配律,用母表示为:(a+b)×c=a×c+b×c.故答案为:乘法分配律,(a+b)×c=a×c+b×c.

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How Many Lies Do the Children Tell You?

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Bella Depaulo and a team of psychologists from the University of Virginia, Charlottesville, asked 77 undergraduates to keep a record of all their conversations for a week, and write down whether they lied at any time. DePaulo named lying broadly, as "when you intentionally try to mislead someone", so she would catch the smallest of lies.

The students told an average of two lies a day. They said they had been studying when they had been out drinking. One told his parents that a textbook cost $50 rather than $20 so that they would send him extra money. Female students constantly told their plain-looking roommates that they were pretty. "They are everyday lies," says DePaulo.

DePaulo and her colleagues conclude that people tend to tell fewer lies to those they feel closest to. College students lied to their best friends 28% of the time but lied to acquaintances 48% of the time. In close relationships, people were more likely to tell "kind-hearted" lies, designed to protect feelings, rather than self-serving lies.

Romantic(浪漫的)partners lie somewhere between close friends and acquaintances. Students lied to romantic partners about a third of the time. DePaulo thinks that unmarried lovers can expect less honesty than best friends because of the insecurity that comes with romance.

Mothers can take heart from one other finding. They may have been lied to, but at least their children talked to them. The students were recorded telling few lies to their fathers because they had little interaction with them.

小题1:What is the meaning of the underlined word "grievance" in Paragraph 1?

A.opinion.

B.complaint.

C.belief.

D.difficulty.小题2: According to the passage, college students felt closest to ______ .

A.mothers

B.best friends

C.acquaintances

D.romantic partners小题3:Female students lied to their roommates to          .

A.get money from them

B.offer them the services

C.gain more security

D.make them happy小题4:What is the purpose of this article?

A.To present a fact.

B.To argue an idea.

C.To tell a story.

D.To explain a theory.

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