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题库 / OG2016V-RC-25
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.
Which of the following best describes the relationship between the first and the second paragraph of the passage?
The first paragraph provides an illustration useful for understanding a procedure described in the second paragraph.
The first paragraph describes a hypothetical situation whose plausibility is tested in the second paragraph.
The first paragraph evaluates the usefulness of a procedure whose application is described further in the second paragraph.
The second paragraph provides evidence to support a claim made in the first paragraph.
The second paragraph analyzes the practical implications of a methodology proposed in the first paragraph.
此讲解的内容由AI生成，还未经人工审阅，仅供参考。
A. 是正确答案。第一段中提到在重力作用下如何测量一个小实心物体的质量，第二段解释了天文学家在双星系统中是如何应用类似的程序来称量双星。因此，第一段给出了一个例子，可以帮助理解第二段所描述的程序。
摘自国外网站的解释，key point是：第二段是原理类比，而非analyze/evaluate/evidence。
The methodology proposed in the first paragraph involves a hypothetical technique for measuring a small solid object’s mass in space (by placing the object on a spring scale and swinging the scale in a circle at the end of a string).
The second paragraph does not discuss practical ways for using THAT hypothetical technique. In other words, the second paragraph does not analyze practical applications of the spring scale/small-solid-object method. Instead, the second paragraph describes a different technique that is analogous to the spring scale/small-solid-object method.
In other words, the second paragraph does not discuss (or analyze) the practical applications of the spring scale/small solid method. Instead, the second paragraph describes an analogous procedure. Furthermore, this analogous procedure is described but is not really analyzed.
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