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
2010-02-17
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 an 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 a scientific 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 then extends them again, 【C17】______ the 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 thousandfold.
【C6】
选项
A、so
B、much
C、rather
D、too
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/7OnK777K
0
专业英语四级
相关试题推荐
TheUSisconsideredamultilingualcountrybutithasneveremployedanofficiallanguagepolicy.EventhoughEnglishisclear
Thedestructionofournaturalresourcesandcontaminationofourfoodsupplycontinuetooccur,largelybecauseoftheextreme
Aprobabletitletothispassagemightbe______.
Yesterdaymyauntboughtsomenew________forherflatattheseaside.
Yesterday’sstrikecausedthemostconfusionfor______.
He______ourwarningandendedupintrouble.
Such______thecase,mistakesareboundtohappenandwemightlandintrouble.
Feelingthatshewasintheright,theoldladytook______atthedirtyremark.
AtlastIrisleftherhouseandgottotherailwaystation,only______thetrainpullingoutofthestation.
Eachoneofthemprayedthathemightleadherhometobehisweddedwife,sogreatlywerethey______atthebeautyofviolet-c
随机试题
吕大爷是糖尿病患者,他的老伴吕大妈十分注意调配他的饮食。吕大妈认为血糖高是因为吃糖引起的,只要饮食中没有糖就不用吃药了。近期,吕大爷因糖尿病并发症住院治疗。出院前,社会工作者小王邀请医生再次向吕大爷夫妇详细讲解了糖尿病与饮食和生活方式的关系,以及控制血糖和
集我国16世纪以前药学大成的本草著作是
组织学表现为恶性者所占比例很高的疾病是
清胆利湿,和胃化痰的方剂是()寒热平调,散结除痰的方剂是()
关于黑社会性质组织犯罪的认定问题,下列说法哪些是正确的?()(2003年卷二第43题)
关于工程咨询公司的不同资质等级所承担的业务范围表述正确的是()。
隧道竣工后,应在直线地段每( )m处加测断面处,测绘以中路线中线为准隧道实际净空。
财务报告企业可以根据需要不定期的编制。( )
根据维纳的两维成败归因理论,稳定的内在原因是()。
Readingliteraturedoesn’tjustimproveyourpowerofimagination./Italsoexpandsyourcapacityforcreativereasoning./As
最新回复
(
0
)