试题与答案

如图所示是小型建筑工地上使用的“罐笼式”提升机,用它能将放在罐笼A中的建筑材料提

题型:计算题

题目:

如图所示是小型建筑工地上使用的“罐笼式”提升机,用它能将放在罐笼A中的建筑材料提升到高处。已知被提升的建筑材料的质量为280kg,拉力F将它以0.5m/s的速度匀速提升到10m的高度,拉力F的功率为2kW。不计摩擦及钢丝绳、动滑轮的重。求:

(1)拉力F对所提升的建筑材料做的功是多少?

(2)罐笼A的重力是多少?

(3)提升机在提升建筑材料时的机械效率是多少?

答案:

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题型:单项选择题

In old days, when a glimpse of stocking was looked upon as something far too shocking to distract the serious work of an office, secretaries were men.

Then came the first World War and the male secretaries were replaced by women. A man’s secretary became his personal servant, charged with remembering his wife’s birthday and buying her presents; taking his suits to the dry cleaners; telling lies on the telephone to keep people he did not wish to speak to at bay and, of course, typing and filing and taking shorthand.

Now all this may be changing again. The microchip and high technology is sweeping the British office, taking with it much of the routine clerical work that secretaries did.

"Once office technology takes over generally, the status of the job will rise again because it will involve only the high-powered work-and then men will want to do it again."

That was said by one of the executives(male) of one of the biggest secretarial agencies in this country. What he has predicted is already under way in the US. One girl described to me a recent temporary job placing men in secretarial jobs in San Francisco. She noted that all the men she dealt with appeared to be gay so possibly that is just a new twist to the old story.

Over here, though, there are men coming onto the job market as secretaries. Classically, girls have learned shorthand and typing and gone into a company to seek their fortune from the bottom——and that’s what happened to John Bowman. Although he joined a national grocery chain as secretary to its first woman senior manager, he has since been promoted to an administration job.

"I filled in the application form and said I could do audio/typing, and in fact I was the only applicant. The girls were reluctant to work for this young, glamorous new woman with all this power in the firm. "

"I did typing at school, and then a commercial course. I just thought it would be useful finding a job. I never got any funny treatment from the girls, though I admit I’ve never met another male secretary. But then I joined the Post Office as a clerk and carelessly played with the typewriter, and wrote letters, and thought that after all secretaries were getting a good £1,000 a year more than clerks like me. There was a shortage at that time, you see. "

"It was simpler working for a woman than for a man. I found she made decisions, she told everybody what she thought, and there was none of that stuff’ ring this number for me dear, which men go in for."

"Don’t forget, we were a team—that’s how I about it—not boss and servant but two people doing different things for the same purpose."

Once high technology has made the job of secretary less routine, will there be male takeover Men should beware of thinking that they can walk right into the better jobs. There are a lot of women secretaries who will do the job as well as they because they are as efficient and well trained to cope with word processors and computers, and men.

John Bowman was given his first job as a secretary because()

A. he was lucky

B. no one else applied

C. he had the best qualifications

D. he wanted to work for a woman

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