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
56
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.
【C14】
选项
A、counterclockwise
B、upside down
C、clockwise
D、anticlockwise
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/iOnK777K
0
专业英语四级
相关试题推荐
"Almostuniversally,womenhavefailedtoreachleadingpositionsinmajorcorporationsandprivatesectororganizations,resp
"Almostuniversally,womenhavefailedtoreachleadingpositionsinmajorcorporationsandprivatesectororganizations,resp
Forcountlesstimesinhistory,peoplehaveexploredtherelationshipbetweenscienceandclassics.Thepioneersoftheteachin
PeoplewhohaveInternetaccessathomearemorelikelytobeinarelationship,withtheWebgaininginimportanceasameetin
Thelandofapplepieandbaseball—theUnitedStatesofAmerica.OfcourseweallknowthereismoretoAmericathanapplepie
FromachildIwasfondofreading,andallthelittlemoneythatcameintomyhandswaseverlaidoutinbooks.Pleasedwithth
Whataretheymainlytalkingabout?
WhenamajorpoweroutageleftevenTimesSquareeerilydark,NewYorkCity’sfaithfulheadedoutoftheirhotapartmentsandst
Thatmanmustbeblind,______heisfeelinghiswayabout.
There’samanatthereceptiondeskwhoseemsveryangryandIthinkhemeans______.trouble.
随机试题
倍增变速机构是由于其传动比按2的倍数增加才称其为倍增变速机构的。()
CT显示子宫颈癌向外后侵犯闭孔内肌和梨状肌,CT分期应属于
新公布的《中华人民共和国传染病防治法》修订通过的时间是()
自汗盗汗属虚证者的治疗原则是
施工单位与建设单位订立施工合同后,将其中的部分工程分包给分包单位,则施工现场的安全生产由()负总责。【2006年考试真题】
王甲应邀到朋友孙乙家喝酒,席间孙乙家的宠物狗在桌边上蹿下跳,王某觉得好玩,不断拿食物喂狗;不料被小狗咬了王甲一口,孙乙告知:这是小狗表示欢迎,没什么问题。酒喝至酣处,孙乙开始兴高采烈向王甲炫耀,自己家祖传的宝贝“明朝的免死金牌”,价值50万元。王
甲公司2011—2013年有关业务如下:(1)甲公司与乙公司签订了一份400万元的劳务合同,甲公司为乙公司开发一套系统软件(以下简称项目)。2011年3月2日项目开发工作开始,预计2013年2月26日完工。预计开发完成该项目的总成本为360万元
闲置能量差异的账务处理多采用调整销货成本与存货法,其他差异则可因企业具体情况而定。()
户外真人秀节目《奔跑吧兄弟》最近热播,收获了较高的关注度和美誉度。作为一种游戏,其过程是随机的,结局是未知的,充满了悬念和不确定性,刺激着人们的观看欲望,调动人们去想象推理。当然,该节目不仅仅满足了观众的娱乐需求,而是在“润物细无声”中传递了正能量。其传递
下面关于文件叙述中错误的是()。
最新回复
(
0
)