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
56
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
Thereareseveralpossiblerelationshipsbetweenlanguageandsociety.Onei
Habitsareafunnything.Wereachforthemmindlessly,settingourbrainsonaut
根据《期货交易管理条例》的规定,在会员分级结算制度下,若某期货公司为非结算会员,则交易所不对该期货公司进行结算,而是直接对客户进行结算。()A
按营运形式不同,公路旅客运输价格可以分为( )。A.班车客运运价 B.包车客
混合成本介于固定成本和变动成本之间,可以分解成固定成本和变动成本两部分。其中的回
用户与计算机通信的界面是()。A.CPU B.外围设备 C.应用程序 D.
薄壁金属电线管中KBG管是()。A.紧定式金属电线管 B.扣压式金属电线管
某天夜里,同宿舍的小赵、小钱、小孙、小李在谈论各自以及隔壁宿舍小周喜欢的电视频道
供应商向企业所提供资源的数量、价格以及供应是否及时、可靠,都会直接影响企业的(
甲公司为制造业企业,2021年到2022年发生的有关业务资料如下: (1)20
最新回复
(
0
)