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
2023-11-23
51
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 speeded up, or the cat’s fall slowed down for the phenomenon to be 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 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 thousand fold. [br] 【C13】
选项
A、though
B、as
C、than
D、and
答案
B
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3213076.html
相关试题推荐
PassageTwo(1)TheAmericanDream,definedastheabilityofeveryU.
PassageTwo(1)TheAmericanDream,definedastheabilityofeveryU.
PassageTwo(1)TheAmericanDream,definedastheabilityofeveryU.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
随机试题
A…………filmindustryB……………movietheatreC…………first—runcinema
WhowontheWorldCup1994footballgame?WhathappenedattheUnitedNa
SincetheUSAgencyforInternationalDevelopment(USAID)beganitsfirstHI
无排卵型月经,首选促排卵的药物为:()A.人工周期疗法 B.雌激素
从所给的四个选项中,选择最合适的一个填入问号处,使之呈现一定的规律性:
地黄饮子主治的病证是A阴虚火旺证 B肝肾阴虚,肝气郁滞证 C肾阳不足证 D
组成普通地图的主体要素部分是()A:数学要素B:地理要素C:辅助要素D:补
国家统计局每年发布的统计公报运用许多重要统计指标和数据反映一年来国民经济和社会发
某市商务中心区两座相邻的高层写字楼,建筑高度分别为68m和54m,耐火等级均为一
下列哪项不是急性糜烂出血性胃炎的常见病因A.非甾体抗炎药 B.脑外伤 C.乙
最新回复
(
0
)