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
A new kind of radar has been developed for space-age travelers. A working laboratory model of a new system of radar that makes u
A new kind of radar has been developed for space-age travelers. A working laboratory model of a new system of radar that makes u
admin
2014-04-23
49
问题
A new kind of radar has been developed for space-age travelers. A working laboratory model of a new system of radar that makes use of a beam of light is said to be ten thousand times more accurate than the best comparable system of radar that uses microwaves.
The model has shown that this radar system (known as laser-doppler radar) can measure with absolute precision speeds varying from spaceship orbital injection velocities (速度) of five miles per second down to virtual stops—speeds of less than one ten thousandth of an inch per second. According to the scientists who are developing this system, such fine measures of velocity are of prime importance in space missions. In a rendezvous (会合, 会合点) between two spaceships, or in a landing approach by a vehicle onto an orbiting space station, a bump could rip open a ship’s skin, or a nudge (轻触) could knock the station out of its orbit.
The light-beam radar, which operates at a frequency of trillions of cycles per second, could easily detect and measure the movement of a vehicle edging up to a satellite space station even at a small fraction of an inch per second. A control system using so precise a signal as this would allow a huge vehicle to dock at a space station as lightly as a feather.
This laser-doppler radar will be especially valuable in space because________.
选项
A、the speeds of space vehicles will vary greatly
B、accurate measurements are essential in space
C、inaccuracies in measurement could cause accidents in space
D、all of the above
答案
D
解析
文中第二段第二句、第三句说:“据正在开发这个系统的科学家说,这样精确的速度测量对于太空飞行来说是头等重要的事情。这种精确的速度测量的重要性在于,当处在两艘宇宙飞船的会合点上,或当一个飞行器在一个轨道太空站进行着陆时,一次轻微碰触就有可能把飞船的外壳撕开一个口子或把太空站撞出其运行轨道。”由此我们可以得出选项B和C都符合题意;又根据文中第二段第一句可知选项A符合题意。而选项D说A、B、C三个选项都对,故本题正确答案为D。
转载请注明原文地址:https://kaotiyun.com/show/QoWO777K
0
在职攻硕英语联考
相关试题推荐
Thesinglegreatestshiftinthehistoryofmass-communicationtechnologyoccurredinthe15thcenturyandwaswelldescribedby
Forlaymenethnologyisprobablythemostinterestingofthebiologicalsciencesfortheveryreasonthatitconcernsanimalsin
AtleastsincetheIndustrialRevolution,genderroleshavebeeninastateoftransition.Asaresult,culturalscriptsaboutm
AtleastsincetheIndustrialRevolution,genderroleshavebeeninastateoftransition.Asaresult,culturalscriptsaboutm
Between1833and1837,thepublishersofa"pennypress"provedthatalow-pricedpaper,editedtointerestordinarypeople,cou
Thereisonlyonedifferencebetweenanoldmanandayoungone:theyoungonehasagloriousfuturebeforehimandtheoldone
Peoplethought:Hey,eatacarpandyouwillbetakinginAwhatitisthatgivesyoutheseBfishtheirlongClife-span.Ofcours
Thereislittlelearninginvolvedwhenoneisreprimandedtwoorthreemonthsafterthedeed.
Assumingthataconstanttravel-timebudget,geographicconstraintsandshort-terminfrastructureconstraintspersistasfundame
PresidentBillClintonisbeingsqueezedontheissueofgaysinthemilitary.Gaysdemandthatheliftthebanonthem.Butthe
随机试题
行政组织建立良好人际关系需坚持平等原则,即要求成员之间
A.单核细胞显著增多B.中性粒细胞显著增多C.淋巴细胞显著增多D.嗜酸性粒细胞显著增多E.嗜碱性粒细胞显著增多
关于进行资产评估有关事项的说明应由()共同撰写。
股权类互换是指()。
下列各项中,不会引起留存收益总额发生增减变动的是()。
A公司2014年销售商品10000件,每件销售单价为100元。单位变动成本为60元,全年固定经营成本为200000元。该公司资产总额为400000元,负债占60%,债务资金的平均利息率为6%,每股净资产为4元。没有优先股。该公司适用的所得税税率为25%。要
物质文化和精神文化并不是平行发展的,更不是互不相干的。在某种物质文化生产的基础上,才产生某种精神文化,我们的古文字的形成及其发展正是古代渔猎社会走向农业社会的结果。农业知识、天文知识、典章制度,直到伦理观念,都是如此。两者不相干的说法,甚至精神文化产生或者
中国进入改革开放和社会主义现代化建设的历史新时期的标志是
[*]
A.thebusinessofthecompanyB.theprincipleofthecompanyC.theproductionofthecompanyD.thescaleofthecomp
最新回复
(
0
)