首页
登录
职称英语
Suppose we were in a spaceship in free fall, where objects are weightless, and w
Suppose we were in a spaceship in free fall, where objects are weightless, and w
游客
2024-01-12
43
管理
问题
Suppose we were in a spaceship in free fall, where objects are weightless, and wanted to know a small solid object’s mass. We could not simply balance that object against another of known weight, as we would on Earth. The unknown mass could be determined, however, by placing the object on a spring scale and swinging the scale in a circle at the end of a string. The scale would measure the tension in the string, which would depend on both the speed of revolution and the mass of the object. The tension would be greater, the greater the mass or the greater the speed of revolution. From the measured tension and speed of whirling, we could determine the object’s mass.
Astronomers use an analogous procedure to "weigh" double-star systems. The speed with which the two stars in a double-star system circle one another depends on the gravitational force between them, which holds the system together. This attractive force, analogous to the tension in the string, is proportional to the stars’ combined mass, according to Newton’s law of gravitation. By observing the time required for the stars to circle each other (the period) and measuring the distance between them, we can deduce the restraining force, and hence the masses. [br] It can be inferred from the passage that the two procedures described in the passage have which of the following in common?
选项
A、They have been applied in practice.
B、They rely on the use of a device that measures tension.
C、Their purpose is to determine an unknown mass.
D、They can only be applied to small solid objects.
E、They involve attraction between objects of similar mass.
答案
C
解析
Inference
The procedures described in the passage are introduced by the suggestion in the first paragraph that someone in a spaceship who wanted to determine a solid object’s mass could do so in a particular way. The second paragraph uses the word weigh in quotes to refer to a similar procedure for determining the mass of a double-star system.
A The language of the first paragraph is hypothetical: we could do particular things. Thus, there is no way to determine from the passage whether that procedure has been applied in practice.
B The first procedure relies on a spring scale, which measures tension, but the second procedure measures time and distance to determine restraining force.
C Correct. Both procedures determine mass: the first procedure can determine the mass of a small solid object on a spaceship in free fall, and the second can determine the mass of a double-star system.
D The first procedure would, according to the passage, be applied to a small solid object, but the second weighs double-star systems, which are clearly not small objects.
E The second procedure involves attraction between two stars, which could be of similar mass, in the same system, but the first procedure involves measuring tension in a string and speed of whirling, not attraction between objects.
The correct answer is C.
转载请注明原文地址:https://tihaiku.com/zcyy/3357142.html
相关试题推荐
Whenyourchildissupposedtobedoinghomework,aretheychattingwiththe
Whenyourchildissupposedtobedoinghomework,aretheychattingwiththe
Whenyourchildissupposedtobedoinghomework,aretheychattingwiththe
Whenyourchildissupposedtobedoinghomework,aretheychattingwiththe
Whenyourchildissupposedtobedoinghomework,aretheychattingwiththe
Whenyourchildissupposedtobedoinghomework,aretheychattingwiththe
Whenyourchildissupposedtobedoinghomework,aretheychattingwiththe
Whenyourchildissupposedtobedoinghomework,aretheychattingwiththe
Whenyourchildissupposedtobedoinghomework,aretheychattingwiththe
Whenyourchildissupposedtobedoinghomework,aretheychattingwiththe
随机试题
STOPSMOKINGDoyouwanttostopsmoking?Haveyoualreadytriedtostop
Inthe(11),theonlyknownway,toIndiafromEuropeinvolvedtraveling
【B1】[br]【B18】A、takeB、goC、putD、callA这里需要一个可与action搭配的动词,作定语从句中的谓语动词修饰action
建设项目财务评价与国民经济评价的区别主要有()。A.评价的角度不同
艾滋病的主要传播途径是A.飞沫传播B.粪-口传播C.血液传播D.虫媒传播E.直接
数据库设计的标准结构为三级模式、二级映射,该结构的主要作用是( )。A.提高数
某村民为盖房欲去山上砍伐几棵国有林木。其儿子说,未经许可去砍伐国有林木是违反森林
社会生态亚系统所具有的功能不包括()。A.人文资源 B.信息的共享、文化教
从所给四个选项中,选出最合适的一个填入问号处,使之呈现一定规律性: A.如上图
混凝土的()使混凝土的碱度降低,削弱混凝土对钢筋的保护作用,可能导致钢筋锈蚀。A
最新回复
(
0
)