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
2024-10-27
10
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] 【C8】
选项
A、by means of
B、by way of
C、in the way of
D、not by
答案
A
解析
by means of意为“通过,借助”,其余几个选项的意思不和题意。
转载请注明原文地址:https://tihaiku.com/zcyy/3819127.html
相关试题推荐
Theabilityoffallingcatstorightthemselvesinmidairandlandontheir
Theabilityoffallingcatstorightthemselvesinmidairandlandontheir
Theabilityoffallingcatstorightthemselvesinmidairandlandontheir
Theabilityoffallingcatstorightthemselvesinmidairandlandontheir
Theabilityoffallingcatstorightthemselvesinmidairandlandontheir
Theabilityoffallingcatstorightthemselvesinmidairandlandontheir
Theabilityoffallingcatstorightthemselvesinmidairandlandontheir
Theabilityoffallingcatstorightthemselvesinmidairandlandontheir
Theabilityoffallingcatstorightthemselvesinmidairandlandontheir
Theabilityoffallingcatstorightthemselvesinmidairandlandontheir
随机试题
Manypeopletodaydreamofbeingtheirownboss,butwhileworkingforyourself
[originaltext]M:Whatdoyouthinkofthegovernment’snewtaxcutproposal?W:T
人体酸碱平衡的调节主要依靠A.以上三者共同作用 B.泌尿系统调节固定酸 C.
下列不属脑卒中的是A、脑出血 B、脑梗死 C、脑动脉硬化症 D、短暂性脑缺
现浇箱涵施工主要工序()。A.砂砾垫层施工 B.基础模板安装与混凝土浇筑
A.负责GAP等认证单位的现场检查认证工作 B.负责组织制定和修订国家药品标准
生产有试行期标准的药品,试行标准期满未按照规定提出转正申请的,应该A.由药品审评
黄土汤与理中丸组成中所共有的药物是A.人参 B.白术 C.干姜 D.黄芩
(2019年真题)期货结算机构的职能不包括()。A.担保交易履约 B.结
某商贸企业从白酒生产企业购进白酒10吨,支付其不含税价格100万元,并
最新回复
(
0
)