visheshsahni wrote:
HelloGMATNinja, I agree with your reasoning. However, I originally chose option D. It seemed to me more like an evidence proving what the author said is not baseless but have some grounds even though 2nd para doesn't 100% follow the same hypothesis.
Quote:
Q3 :- Which of the following best describes the relationship between the first and the second paragraph of the passage?
D The second paragraph provides evidence to support a claim made in the first paragraph.
For us to accept (D) as the best possible choice, we need to identify the claim made in P1. Then we need to identify how P2 provides evidence to support that claim.
Quote:
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 [gl]string[/gl], 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.
P1 presents a hypothetical scenario, where we determine the mass of an object inside a spaceship that's in free fall. P1 makes the claim that in this scenario, we could attach a spring scale to the object using a string, then determine the weight of the mass of the object by measuring the tension in the string. But why is the author bringing this up? So far, it seems like the only purpose of this paragraph is to tell us about this specific method, and how it works in this specific scenario.
Quote:
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.
Can we say that P2
presents evidence to support the claim made in P1? Nope. Here's why:
- P2 doesn't give us any more information about the scale, the string, the physics of free fall, or the math that's being done to measure the mass of the object that is discussed in P1. If (D) were correct, we'd expect to see P2 show concrete proof, in order to further convince us that the procedure described in P1 works.
- Instead, P2 describes a completely different case, where we determine the masses of stars by measuring the time required for the stars to circle each other as well as the distance between them. Throughout P2, the author brings up analogous details in P1 in order to helps us understand this more cosmic, less tangible procedure.
Once we read the whole passage, we see that the purpose of P1 was to make it easier for us to understand P2. This is
not the same as using P2 to strengthen a claim made in P1, so we eliminate (D).
I hope this helps!