首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Why were the Wright brothers able to succeed in an effort at which so many others had failed? Many explanations have been mentio
Why were the Wright brothers able to succeed in an effort at which so many others had failed? Many explanations have been mentio
admin
2011-02-28
31
问题
Why were the Wright brothers able to succeed in an effort at which so many others had failed? Many explanations have been mentioned, but three reasons are most often cited. First, they were a team. Both men worked congenially and cooperatively, talked incessantly about the possibility of manned flight, and served as a conscious source of inspiration and encouragement to each other.
Both were glider pilots. Unlike some other engineers who experimented with the theories of flight, they experienced the practical aspects of aerodynamics by building and flying in kites and gliders. They had realized from their experiments that the most serious challenge in manned flight would be stabilizing and maneuvering the aircraft once it was airborne. While others concentrated their efforts on the problem of achieving lift for take-off, they were focusing on developing a three- axis control for guiding their aircraft.
In addition, the Wright brothers had designed more effective wings for the airplane than had been previously engineered. Using a wind tunnel, they tested more than two hundred different wing designs, recording the effects of slight variations in shape on the pressure of air on the wings. The data from these experiments allowed the Wright brothers to construct a superior’ wing for their aircraft.
In spite of these advantages, however, the Wright brothers might not have succeeded had they not been born at precisely the opportune moment in history. Attempts to achieve manned flight in the early nineteenth century were doomed because the steam engines that powered the aircrafts were so heavy in proportion to the power that they produced. But by the end of the nineteenth century, when the brothers were experimenting with engineering options, a relatively light internal combustion engine had already been invented, and they were able to bring the ratio of weight to power within acceptable limits for flight.
In the fourth paragraph, the author suggests that the steam’ engine used in the earlier aircrafts had failed because they ______.
选项
A、were too small to power a large plane
B、were too light to generate enough power
C、didn’t have internal combustion power
D、didn’t have enough power to lift their own weight
答案
D
解析
由第四段中的第二句the steam engines that powered the aircrafts were so heavy in proportion to the power that they produced可知,蒸汽机自身的重量和它提供的动力比例失调。
转载请注明原文地址:https://kaotiyun.com/show/BWtd777K
本试题收录于:
公共英语三级笔试题库公共英语(PETS)分类
0
公共英语三级笔试
公共英语(PETS)
相关试题推荐
Schoolsofeducationhavelongbeenobjectsofcriticism.FromJamesKoerner’s1963book,TheMiseducationofAmerica’sTeachers
Schoolsofeducationhavelongbeenobjectsofcriticism.FromJamesKoerner’s1963book,TheMiseducationofAmerica’sTeachers
Schoolsofeducationhavelongbeenobjectsofcriticism.FromJamesKoerner’s1963book,TheMiseducationofAmerica’sTeachers
Whydidthedrivermentionhiswife’scousin’shusband?
Wecaninferfromthetextthat______.WhichofthefollowingisNOTmentionedinthetextaboutsomeparents’attitudestowar
Belowarepicturesshowingtwomothersteachtheirchildrendifferentlyhowtotreattheelderly.Lookatthepicturesandwrite
Whatisthetoneofthestory?Whydoestheauthormentionstuffeddrugsmugglers?
Theexamplestheauthormentionsinthefirstparagraphisto______.WhathappenedtothecalendarofFranceintheyear1562
WhichofthefollowingfactorisNOTmentionedwhendiscussingthepersonsinterviewedintheresearch?Whatisthebesttitle
随机试题
柱塞气举是()气举的一种形式。
背景材料张山是一家跨国公司的销售人员,常驻沙特阿拉伯,跟当地客户的合作和关系都很好,私人关系也不错。有一次,他的亲人来到沙特阿拉伯看望他,带来了他非常喜欢吃的王中王猪肉火腿肠。他为了表示自己对客户的友谊,打算把这些火腿肠与当地合作伙伴进行分享。问题:
消风散中使用的养血活血药是
中等城市的工程质量监督费按受监理工程建筑安装工程量的()计收。
期货公司对外发布的广告宣传材料,应当自发布之日起5个T作日内报住所地的中国证监会派出机构备案。()
按照不同的发行标的,国债可以分为实物国债和货币国债。()
素质教育最突出的特点是()。
甲将自己的汽车抵押给乙,作价5万元,甲继续使用。结果甲开车时不小心将车撞坏。下列说法正确的是()。
在满足实体完整性约束的条件下
Heisexemptedfrommilitaryservice,becauseofhisbadsight.
最新回复
(
0
)