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
An Interesting Phenomenon The ability of falling cats to right themselves in midair and land on their feet has been a source
An Interesting Phenomenon The ability of falling cats to right themselves in midair and land on their feet has been a source
admin
2012-04-23
50
问题
An Interesting Phenomenon
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 adaptation by natural selection, but for physicists it bordered on the miraculous. Newton’s laws of motion assume that the total amount of spin of a body cannot change unless an external torque speeds it up or slows it down. If a cat has no spin when it is released and experiences no external toque, it ought not to be able to twist around as it falls.
In the speed of its execution, the righting of a tumbling cat resembles a magician’s trick. The gyrations of the cat in midair are too fast for the human eye to follow, so the process is obscured. Either the eye must be speeded up, or the cat’s fall be slowed down for the phenomenon to be observed. A century ago the former was accomplished by means of high -speed photography using equipment now available in any pharmacy. But in the nineteenth century the capture 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 each, one from the side and one from behind, show a white cat in the act of righting itself. Grainy and quaint though 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 clockwise, the rear and tail-twist counterclockwise, so that the total spin remains zero, in perfect accord with Newton’s laws. Halfway down, the cat pulls in its legs before reversing its twist and then extends them again, with the desired end result. The explanation was that while no body can acquire spin without torque, a flexible one can readily change its orientation, or phase. Cats know this instinctively, but scientists could not be sure how it happened until they increased the speed of their perceptions a thousand fold.
Which of the following can be inferred about high - speed photography in the late 1800’s?
选项
A、It was a relatively new technology.
B、The necessary equipment was easy to obtain.
C、The resulting photographs are difficult to interpret.
D、It was not fast enough to provide new information.
答案
A
解析
从第二段最后两句可推断出现在已经非常普遍的摄影技术,在当时还是一种很新的技术,因而其设备肯定也是不容易弄到的,故B不对,而C、D与文中结论正好相反,所以答案应为A。
转载请注明原文地址:https://kaotiyun.com/show/EFiO777K
0
专业英语八级
相关试题推荐
Canada’sEducationSystemTheCanadiangovernmentprovides【1】publiceducationforallstudentsfromKindergartentoGrade12.
Antarcticahasactuallybecomeakindofspacestation—auniqueobservationpostfordetectingimportantchangesintheworld’s
YellowFeverItisclearthattomanypeopleintheUStheideaofagroupofforeignmusiciansundertakingaconcerttourof
A、governmentalcorruptionB、hightaxesandlowpaysC、poormedicalserviceD、unemploymentandpovertyD
A、whohadattackedagainstIsraelicitizensB、whoareingoodhealthC、wholivedalongtheGazaStripD、whohaveservedthemajo
Cyberspace,datasuperhighways,multi-media--forthosewhohaveseenthefuture,thelinkingofcomputers,televisionandteleph
TheFutureofPCMarketThefirstDevelopersConferenceinChinamarksamajormilestoneforMicrosoft,becausethesuccesso
Computers,andespeciallyconnectingtotheInternet,provideuniqueopportunitiestoenhancescienceandmatheducation.Tak
WhatmightbethetargetoftheIsraeliraid?
我直到几十年以后,才体会到云彩更多,霞光才愈美丽。从云翳中外露的霞光,才是璀璨多彩的。生命中不是只有快乐,也不是只有痛苦,快乐和痛苦是相生相成,互相衬托的。快乐是一抹徽云.痛苦是压城的乌云.这不同的云彩。在你生命的天边重叠着,在“夕阳无限好”的
随机试题
后天各种因素使体质具有
关于二尖瓣关闭不全和二尖瓣狭窄的比较,错误的是
A公司中标某城市污水处理厂的中水扩建工程,合同工期10个月,合同价为固定总价,工程主要包括沉淀池和滤池等现浇混凝土水池。拟建水池距现有建(构)筑物最近距离5m,其地下部分最深为3.6m,厂区地下水位在地面下约2.0m。A公司施工项目部编制了施工组织
准确性原则要求基金信息必须按照法定的内容和格式进行披露。()
债券投资业务中,债券票面利息与购买价格之间的比率为()。
下列符合企业所得税佣金扣除规定,可以在企业所得税税前全额扣除的佣金是()。
下列哪种物品不属于扣押的范围?()
你在单位,工作能力强、思想觉悟高,领导很看好你.但新来了一个同事,他学历高、能力强,人们都说一山不容二虎。你将如何与他搞好关系?
大凡作诗填词,都是语言与情感互相迁就的过程。一位初学者最初萌生什么样的感情,选择什么样的句式来起手,是不可预知的。可是一旦他有了初步的构思,就总能在《唐宋词格律》这部书里得到适当的帮助。他会知道用哪些词牌适合表达怎样的感情,应该选择什么样的韵脚,以及怎样合
计算机网络系统的远程通信通常是( )
最新回复
(
0
)