问题 选择题

一只船在静水中的速度恒为4m/s,它要渡过一条宽度为200m的河,河水的流速恒为3m/s.则下列说法中正确的是(  )

A.船不可能渡过河

B.船不可能垂直到达对岸

C.船到达对岸最小位移大于200m

D.船到达对岸所需时间最小是50s

答案

A、D、当船头指向始终垂直于河岸时,渡河时间最短,最短时间为tmin=

d
vc
=
200
4
s=50s,当船头指向与河岸不垂直时,船垂直于河岸方向的分速度变小,渡河时间变长.故A错误,D正确;

B、C、由于船相对于水的速度大于水流速度,根据平行四边形定则可知,它们的合速度,即船实际的速度可以与河岸垂直,船可以垂直于河岸行驶,最终到达对岸,最小位移等于200m,故BC错误;

故选:D.

阅读理解

A jobless man applied for the position of “office boy”at Microsoft.The HR manager interviewed him and then watched him cleaning the floor as a test.

“You are employed.”he said.”Give me our e-mail address and I’ll send you the application to fill in ,as well as date when you may start.”

The man replied,”But Idon’t have a computer,neither an e-mail.”

“I’m sorry,”said the HR manager,”If you don’t have an e-mail,that means you do not exist.And who doesn’t exist cannot have the job.”

The man left with no hope at all.He didn’t know what to do, with only ten dollars in his pocket.He then decided to go to the supermarket and buy 10kg tomatoes.He then sold the tomatoes from door to door.In less than two hours,he succeded to double his capital,He repeated the operation three times,and returned home happily with 60 dollars.

The man realized that he can survive in this way,and started to go every day earlier,and return late,Thus,his money doubled or tripled every day.Shortly,he bought a cart,then a truck,and then he had his own fleet of delivery vehicles.Five years later,the man is one of the biggest food retailers in the US.

He started to plan his family’s future and decided to have a life insurance He called an insurance broker and chose a protection plan.

When the conversation was concluded the broker asked him his e-mail,The man replied,”I don’t have an e-mail.”

The broker answered curiously,”You don’t have an e-mail,and yet have succeeded to build an empire.Can you imagine what you could have been if you had an e-mail?”The man thought for a while and replied,”Yes,I’d be an office boy at Microsoft!”

小题1:Why can’t the man have the job at Microsoft?

A.Because he didn’t have an e-mail

B.B Because he was lazy.

C.Because he didn’t pass the test

D.Because he didn’t have a computer小题2:The underlined word “triple”can be replaced by_______.

A.become 3 times

B.become large

C.increase quickly

D.decrease quickly小题3:According to the passage,which of the following is TRUE?

A.The man is one of the biggest food retailers in the world.

B.The man didn’t give up though he failed the interview.

C.He started his career by selling tomatoes in the supermarket.

D.Those who have e-mails can work at Microsoft.小题4:The man can be described as ______.

A.helpful and considerate

B.smart and hardworking

C.positive and generous

D.stubborn and unselfish小题5:Which proverb can best describe the story?

A.Where there is a will,there is a way.

B.Accidents will happen.

C.Misfortune may be an actual blessing.

D.No pains,no gains.

单项选择题