首页
登录
职称英语
The ability of falling cats to right themselves in midair and land on their
The ability of falling cats to right themselves in midair and land on their
游客
2023-11-20
34
管理
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. [br] 【C11】
选项
A、respectively
B、each
C、all
D、more
答案
B
解析
题意是每组20张照片,只能选B。
转载请注明原文地址:https://tihaiku.com/zcyy/3204568.html
相关试题推荐
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Allpeoplehavesomeabilitytomanagetheirhealthandthehealthofthose
Allpeoplehavesomeabilitytomanagetheirhealthandthehealthofthose
Allpeoplehavesomeabilitytomanagetheirhealthandthehealthofthose
随机试题
[originaltext](22)AbigdifferencebetweenpublicandprivateinAmericanh
ThedarksmokethatcomesoutofStacksorfromaburningdumpcontainstiny
ItoftenseemsthateveryoneinBritainhasamobilephone.Weusethemasa
几年前,北京的打工族们(migrantworkers)经常抱怨买不起房子。令他们意想不到的是,现在租房子也变成了难事。相关部门发布的最新数据显示,今年
下列关于流通国债的特征,说法错误的是( )。A.投资者可以自由认购 B.投资
某国外汽车公司欲在我国投资建设家用轿车生产厂,聘请一家咨询单位进行相关的市场咨询
药物鉴别的主要目的是()A.检查药物的纯度 B.判断药物的稳定性 C
胆汁中有利胆作用的是A.胆固醇 B.胆色素 C.胆盐 D.胆绿素 E.脂
某建设项目工程费用5000万元,工程建设其他费用1000万元,基本预备费
关于环境管理体系说法正确的有()。A.环境管理体系要求及使用指南包括10部分
最新回复
(
0
)