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
50
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] 【C4】
选项
A、tumble down
B、twist around
C、topple down
D、stumble over
答案
B
解析
转载请注明原文地址:http://tihaiku.com/zcyy/3213067.html
相关试题推荐
PassageTwo(1)TheAmericanDream,definedastheabilityofeveryU.
PassageTwo(1)TheAmericanDream,definedastheabilityofeveryU.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Humanity’shighlydevelopedabilitytocommunicateverballyisouressence.
Allpeoplehavesomeabilitytomanagetheirhealthandthehealthofthose
Allpeoplehavesomeabilitytomanagetheirhealthandthehealthofthose
Allpeoplehavesomeabilitytomanagetheirhealthandthehealthofthose
Allpeoplehavesomeabilitytomanagetheirhealthandthehealthofthose
随机试题
ThebiggestproblemfacingChileasitpromotesitselfasatouristdestinati
AsthemerchantmanclassexpandedintheeighteenthcenturyNorth1.______.
[originaltext]W:Tellmealittlebitaboutyourself,please.M:MynameisDav
Childrenwhostartspeakinglate______.[br]Itcanbeinferredfromthepassag
放学的时候,有幼儿家长看到孩子自己穿衣服,而老师却站在一旁不帮忙,就走过来斥责老
首过消除最显著的给药途径是A.舌下给药 B.吸入给药 C.静脉给药 D.皮
(2014年真题)根据保罗赫塞的领导者生命周期理论,员工的知识技能水平决定(
背景资料 某施工单位承接了某市一座双向四车道分离式隧道施工,单洞设计为9.
下列用工项目中,属于预算定额与劳动定额人工幅度差的是()。A:施工机械辅助用工
妊娠期母体血容量增加的时期正确的是( )。A.始于妊娠期4~6周,37~38周
最新回复
(
0
)