试题与答案

如图所示,质量为1kg的木块静止于水平面上,与轻质弹簧的下端相连,轻质弹簧处于自

题型:选择题

题目:

如图所示,质量为1kg的木块静止于水平面上,与轻质弹簧的下端相连,轻质弹簧处于自然伸直状态,现用恒定的竖直向上的外力F作用于弹簧上端,在木块向上移动一段距离的过程中拉力F做了100J的功,在上述过程中(  )

A.弹簧的弹性势能增加了100J

B.木块的动能增加了100J

C.木块和弹簧组成的系统机械能增加了100J

D.木块的重力势能增加了100J

答案:

在外力做功的过程中,弹簧的弹性势能增加,木块的动能和重力势能统称为木块的机械能,而木块的机械能也增加.功是能量转化的量度,可知外力所作的功,使得弹簧的弹性势能和木块的机械能增加.故A、B、D错误,C正确.

故选C.

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题型:阅读理解
For many in the United States,Arab-Americans are an invisible part of the population.Though Arab-Americans as a community have made great contributions to American society in fields from literature to politics to medicine,many Americans know very little about Americans of Arab backgrounds.
Arab history in the United States goes back to the late 1800’s when large numbers of Arab immigrants first began making their journey to a land known simply as“Amreeka”.
Historians generally describe Arab immigration to America in two waves.The first wave took place between 1860 and 1924.The first wave consisted of Lebanese and Syrian,and some Egyptian immigrants.These new immigrants,who were mostly Christian,came to America in search of better opportunities.Even the doomed Titanic,which set sail for America in 1912,had close to a hundred Arab passengers aboard.The majority of Arab-Americans today are descendents of the first wave of immigrants;they are the third or more generation Americans.
The second wave of immigrants followed after World War Ⅱ,caused by political unrest in the Middle East.This second wave of immigrants consists of mainly Arab Muslims(穆斯林)and continues to this day.
Arab-Americans make up 3 million of the population in the United States,according to demographers.And quite different from popular belief,64 percent of them are American-born.Eighty-two percent of Arab-Americans are US citizens.
Arab-Americans are beyond the national average in both education and income.Education is important among Arab-Americans;82 percent have high school diplomas,36 percent have bachelor’s degrees or higher,and 15 percent have graduate degrees.The-median(中位数的) average income among Arab-Americans is $39 580,which is higher than the US average.
小题1: What would be the best title for the text?
A.Arabs in America.B.The Two Arab Immigration Waves to America.
C.Arab-Americans,Contributions to America.
D.Arab-Americans,Education and Income.
小题2:The first wave of immigrants took place because______.
A.all Arabs were Christian at that time
B.Arabs wanted to hunt for a better development
C.the Second World War broke out
D.Arabs wanted to gain higher income
小题3:The writer of this passage mentioned Titanic______.
A.to tell us that taking ship at that time was dangerous
B.because Titanic became a well-known disaster
C.to show us there were many Arabs flocking into America at that time
D.to inform us that Arabs are brave enough
小题4:From the last paragraph we can infer that______.
A.Arab-Americans are much more clever than native Americans
B.Arab-Americans are hard-working people
C.the higher education you receive,the higher income you will get in America
D.Arab-Americans play the most important role in the American average in both education and income
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