OG2020每日閱讀訓練練習D5

Pistachio_lin

Hi 大家好, 打卡閱讀訓練D5.

Materials/sources: OG2020

Passage:

    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.

簡化/邏輯思路


    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. (第一句給了一個情況 - 猜測了一下大概想說在那個情況我們能做什麼？或是在那個情況下研究什麼。接下來的句子闡明，量測方法的適用性，以及該如何在free fall的情況下測量; 總結: 透過測量tension，我們能知道一個物體的重量。 這一段其實在講一個process. 跟透過這個process我們能做什麼)

    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. (第一句話有承上啟下的作用，上一段介紹了一個process, 這句話astronomers用這個方法測量double-star system. 接著說 speed與gravitational之間的關係，進而在下一步引導出這個引力 - 類比為tension in string" - 跟星星合在一起的重量成比例關係. 最後說我們能導出masses)

總結
第一段: 說明一個情況，以及引出一種在此情況下適用的方法。
第二段: 說明某個領域的人使用類似的方法能成功得到想要的結果。


1. It can be inferred from the passage that the two procedures described in the passage have which of the following in common?

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. (定位第一段, - 有個however, 說明了那個地方會是考點 -第一段說明是在測量不知道mass的東西, 第二段說，astronomers用的手法類似於上段所說的手法概念，目的都是在做一樣的事情)
D They can only be applied to small solid objects.
E They involve attraction between objects of similar mass.

2. According to the passage, the tension in the string mentioned in highlight text is analogous to which of the following aspects of a double-star system?

A The speed with which one star orbits the other
B The gravitational attraction between the stars (定位第二段, this attractive force, analogous to the tension in the string)
C The amount of time it takes for the stars to circle one another
D The distance between the two stars
E The combined mass of the two stars


3. Which of the following best describes the relationship between the first and the second paragraph of the passage?

A The first paragraph provides an illustration useful for understanding a procedure described in the second paragraph. (同段落分析，講第一段的目的，是為了讓我們能更清楚的明白astronomers們是如何求的masses. *兩種手法非相同，但相似)
B The first paragraph describes a hypothetical situation whose plausibility is tested in the second paragraph. (沒有在第二段中驗證第一段所提到的這個手法，只有用這個手法去提供一種解讀)
C The first paragraph evaluates the usefulness of a procedure whose application is described further in the second paragraph. (沒提到)
D The second paragraph provides evidence to support a claim made in the first paragraph. (沒提到)
E The second paragraph analyzes the practical implications of a methodology proposed in the first paragraph. (同B選項分析)


4. The author of the passage mentions observations regarding the period of a double-star system as being useful for determining

A the distance between the two stars in the system
B the time it takes for each star to rotate on its axis
C the size of the orbit the system's two stars occupy
D the degree of gravitational attraction between the system's stars (接續在描述this attractive force後而寫的; 文中也有提到是為了觀察"兩個星球彼此旋轉的時間", 而兩個星球彼此旋轉之間會有attractive force在之中)
E the speed at which the star system moves through space