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
The ability of falling cats to right themselves in midair and land on their feet has been a source of wonder for ages. Biologist
The ability of falling cats to right themselves in midair and land on their feet has been a source of wonder for ages. Biologist
admin
2010-03-19
33
问题
The ability of falling cats to right themselves in midair and land on their feet has been a source of wonder for ages. Biologists long regarded it as all example of 【C1】______ by natural selection, but for physicists it bordered on the miraculous. Newton’s laws of motion 【C2】______ that the total amount of spin of a body cannot change 【C3】______ an external torque speeds it up or slows it down. If a cat has no spin when it is released and experiences no external torque, it ought not to be able to 【C4】______ as it falls. In the speed of its execution, the 【C5】______ of a tumbling cat resembles a magician’s trick. The gyrations of the cat in midair are 【C6】______ fast for the human eye to follow, so the process is obscured. 【C7】______ the eye must be speeded up, or the cat’s fall slowed down for the phenomenon to be observed. A century ago the former was accomplished 【C8】______ high-speed photography using equipment now 【C9】______ in any pharmacy. But in the nineteenth century the 【C10】______ on film of a falling cat constituted ascientific experiment. The experiment was described in a paper presented to the Paris Academy in 1894. Two sequences of twenty photographs 【C11】______ one from the side and one from behind, 【C12】______ a white cat in the act of righting itself. Grainy and quaint 【C13】______ they are, the photos show that the cat was dropped upside down, with no initial spin, and still landed on its feet. Careful analysis of the photos reveals the secret. As the cat rotates the front of its body 【C14】______ , the rear and tail twist counterclockwise, 【C15】______ the total spin remains zero, 【C16】______ Newton’s laws. Halfway down, the cat pulls in its legs before reversing its twist and them extends them again, 【C17】______ he desired end result. The explanation was that while no body can acquire spin without torque, a flexible one can readily change its 【C18】______ . Cats know this instinctively, but scientists could not be sure how it happened 【C19】______ they increased the speed of their 【C20】______ a thousand fold.
【C14】
选项
A、counterclockwise
B、upside down
C、clockwise
D、anticlockwise
答案
C
解析
根据下文的counterclockwise,此处应该是与之相反的,所以正确答案是C。
转载请注明原文地址:https://kaotiyun.com/show/lq9K777K
0
专业英语四级
相关试题推荐
Publicofficialsandcandidatesforpublicofficeroutinelyusepublicopinionpollstokeeptrackofwhatthepeoplearethinki
Businessandgovernmentleadersalsoconsidertheinflationratetobeanimportantgeneralindicator.Inflationisaperiodof
Whataretheymainlytalkingabout?
Attentiontodetailsissomethingeveryonecanandshoulddo--especiallyinatightjobmarket.BobCrossIcy,ahuman-resources
Shepossessedaquickmind,asharptongueand______astrongwill.
EducationalTVstationsofferteachinginvarious______rangingfromhomenursingtoartappreciation.
Whohavelaunchedacampaigntodefendtherightofwearinghijab?
Thetrainclatteredoverpointsandpassedthroughastation.Thenitbegansuddenlytoslowdown,presumablyinobediencetoa
WriteonANSWERSHEETTWOanoteofabout50~60wordsbasedonthefollowingsituation:Youjustgotrecoveredfromillness.
Hewentbacktoworkafterhehadrecoveredfromhisillness______thattheyhadfoundanotherpersontoreplacehim.
随机试题
某实验室要制定一个机械天平的期间核查方案,基本确定:机械天平每三月对1.0000g,100.0000g两个点进行一次核查,请你考虑并给出一个核查方案的初稿。
写明由领导人亲收亲启的封件,应由哪些人拆封()
鞣质与下列物质中不能产生沉淀的是
男性,42岁,毕Ⅱ式胃大部切除术后2年,上腹部有烧灼感,抗酸药治疗无效,有时呕吐,内含胆汁,吐后腹痛无缓解,体重减轻,胃镜下黏膜充血、水肿、易出血。最可能的诊断是
乌药具有的功效是
颜色是矿物最明显、最直观的物理性质,其中()是矿物本身固有的成分、结构所决定的颜色,具有鉴定意义。
在财务分析中,分析的目的是对企业财务状况及经营成果作出准确判断以提高企业的经营管理水平的是()。
下列税务机关中,虽然不具有税务处罚主体资格、但可以实税务行政处罚的是()。
(1)设系统由100个相互独立的部件组成.运行期间每个部件损坏的概率为0.1.至少有85个部件是完好时系统才能正常工作,求系统正常T作的概率.Ф()=0.9522.(2)如果上述系统由n个部件组成,至少有80%的部件完好时系统才能正常工作.问n至
A、Everyspeciesbecomesextinct.B、Humansbeingsarepowerfulenoughtokillotherspecies.C、Thepopulationofhumanbeingsis
最新回复
(
0
)