问题 选择题

在离地面3米高的天花板下用一根长为1m的绳吊着一个10N的物体,若取地面为重力势能零势能面,则该物体的重力势能为(  )

A.10J

B.20J

C.30J

D.无法确定

答案

以地面为重力势能零势能面,则物体的高度h=2m,则EP=mgh=10×2J=20J.故B正确,A、C、D错误.

故选B.

改错题

第二节 短文改错(每小题1.5分,共15分)

此题要求改正所给短文的错误。对标有题号的每一行作出判断:如无错误,在该行右边横线上划一个勾(√);如有错误(每行只有一个错误),则按下列情况改正:

该行多一个词:把多余的词用斜线(\)划掉,在该行右边横线上写出该词,并也用斜线划掉。

该行缺一个词:在缺词处加一个漏字符号(∧),在该行右边横线上写出该加的词。

该行错一个词:在错的词下划一横线,在该行右边横线上写出改正后的词。

注意:原行没有错的不要改。

It happened in a morning that I was walking in the street .                 76.___________

I ate up a banana and threw its peel on the corner of the road               77.___________

Shortly after that I hear a scream behind .I looked back to                 78.___________

see what was happened .A little girl about 8 years old fell                  79.___________

down and the banana peel was exactly under his left shoe                   80.___________

She stood up without cry .Then she picked up the banana peel       81.___________

and ran toward the dustbin .

On that moment ,I realized my fault , and went to                        82.___________

apologize her for that ,but my vanity (虚荣心)prevented me .               83.___________

The little girl had taught me a good lesson by her action .                  84.___________

And now, after I do everything , I'll think carefully whether       85.___________

it's right or wrong . I'll do my best to be in good habits and

Qualities.

多项选择题