把一个物体放在倾角为37°的斜面上,物体处于静止状态,已知物体受斜面的支持力大小为40 N,受斜面的摩擦力大小为30 N.求这两个力的合力. 答案:50 N 与支持力的夹角为37°(或竖直向上) 解析:解法一:用作图法求解.设支持力为F1,方向垂直于斜面向上,摩擦力为F2,方向沿斜面向上,选定某一标度,如用5 mm长的线段表示10 N的力,作出F1、F2的图示,然后以F1、F2为邻边作平行四边形,如下图所示. 用刻度尺量得表示合力F的对角线长25 mm,When I was growing up in America, I was ashamed of my
mother’s Chinese English. Because of her English, she was often treated
unfairly. People in department stores, at banks, and at restaurants did not
take her seriously, did not give her good service, pretended not to understand
her, or even acted as if they did not hear her.
My mother
has long realized the limitations of her English as well. When I was fifteen,
she used to have me call people on the phone to pretend I was she. I was forced
to ask for information or even to yell at people who had been rude to her. One
time I had to call her stockbroker (股票经纪人). I said
in an adolescent voice that was not very convincing, "This is Mrs. Tan.”
And my
mother was standing beside me, whispering loudly, "Why he don’t send me
check, already two week late.”
And then, in
perfect English I said, "I’m getting rather concerned. You agreed to send
the check two weeks ago, but it hasn’t arrived. "
Then she
talked more loudly. "What he want? I come to New York tell him front
of his boss. "And so I turned to the stockbroker again, "I can’t
tolerate any more excuse. If I don’t receive the check immediately, I am going
to have to speak to your manager when I am in New York next week. "
The next
week we ended up in New York. While I was sitting there red-faced, my mother,
the real Mrs. Tan, was shouting to his boss in her broken English.
When I was a
teenager, my mother’s broken English embarrassed me. But now, I see it differently.
To me, my mother’s English is perfectly clear, perfectly natural. It is my
mother tongue. Her language, as I hear it, is vivid, direct, and full of
observation and wisdom. It was the language that helped shape the way I saw
things, expressed ideas, and made sense of the world.
1.Why was the author’s mother poorly served?
A.She was
unable to speak good English. B.She was often
misunderstood.
C.She was not
clearly heard. D.She was not
very polite.
2.From Paragraph 2,we know that the author was .
A.good at
pretending B.rude to the
stockbroker
C.ready to help
her mother D.unwilling to
phone for her mother
3.After the author made the phone call, .
A.they forgave
the stockbroker B.they failed
to get the check
C.they went to
New York at once D.they spoke to
their boss at once
4.What does the author think of her mother’s English
now?
A.It confuses
her. B.It makes her
ashamed
C.It helps her
understand the world. D.It helps her
bear rude people.
5.We can infer from the passage that Chinese English
.
A.is clear and
natural to non-native speakers
B.is
interesting and straight to non-native speakers
C.leaves a very
bad impression on America
D.may bring
inconvenience in America