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. Biolo
The ability of falling cats to right themselves in midair and land on their feet has been a source of wonder for ages. Biolo
admin
2009-01-05
17
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.
【C18】
选项
A、movement
B、orientation
C、behavior
D、adjustment
答案
B
解析
转载请注明原文地址:https://kaotiyun.com/show/kcBK777K
0
专业英语四级
相关试题推荐
PositiveforYouthaimstoplaceteenagersandyoungpeopleatitsheart.Thereistheaccurateexpectationteenagersthemselves
PositiveforYouthaimstoplaceteenagersandyoungpeopleatitsheart.Thereistheaccurateexpectationteenagersthemselves
PositiveforYouthaimstoplaceteenagersandyoungpeopleatitsheart.Thereistheaccurateexpectationteenagersthemselves
PositiveforYouthaimstoplaceteenagersandyoungpeopleatitsheart.Thereistheaccurateexpectationteenagersthemselves
PositiveforYouthaimstoplaceteenagersandyoungpeopleatitsheart.Thereistheaccurateexpectationteenagersthemselves
PositiveforYouthaimstoplaceteenagersandyoungpeopleatitsheart.Thereistheaccurateexpectationteenagersthemselves
Formany,thepursuitofhappinessisalsothepursuitofprosperity.PartoftheAmericandreamistheabilitytoprovide【M1】__
随机试题
下列关于公安机关办理治安案件期限的说法错误的是()。
梯度磁场强度变化通常为
社会研究中常用的信度类型主要包括()
急性性肾功能衰竭多尿期可见到的水、电解质紊乱有
A.肺气肿B.肺不张C.肺水肿D.肺脓肿E.肺褐色硬化肺末梢组织充气过度导致
患者,男,56岁。有高血压病史4年。体检:血压156/96mmHg,无主动脉狭窄。医师处方依那普利片控制血压。服用2个月后,血压控制未达标,经进一步检查,该患者伴有同型半胱氨酸水平升高,宜联合应用的药品是()
上海东华进出口公司进口一批由香港某贸易公司购自日本的迷你塑料玩具和手表。运输货物的运输工具于2003年1月21日申报进境,1月26日,上海保通报关行向上海海关申报货物进口。
递延年金的特点有( )。Ⅰ.最初若干期没有收付款项Ⅱ.最后若干期没有收付款项Ⅲ.其终值计算与普通年金相同Ⅳ.其现值计算与普通年金相同
国有企业改造为公司制企业时,在评估基准日与建账日之间可能发生盈亏。下列各企业中,应享有或承担此盈亏的是()。
培训过程中要以实际操作来印证、深化培训的具体内容,坚持()。
最新回复
(
0
)