Free Practice Question
RC · Reading Comprehension
sub-505
Short Passage - Science
Reading 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.
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.
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?
Answer Choices
Correct answer marked belowA
The speed with which one star orbits the other
The gravitational attraction between the stars
Correct
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
See the full step-by-step explanation
You can see the correct answer above. Sign in for free to unlock the complete worked solution.
Track your performance and improve
Get detailed analytics, unlock full explanations, and move up difficulty tiers as you practice.
Explanation
Unlock the full explanation
Create a free account to reveal the correct answer, see the step-by-step explanation, and start tracking your GMAT progress.
Comments
Sign in to join the discussion
No comments yet
Be the first to share your thoughts and help others understand it better.
Sign in to commentWhat this question tests
What it tests
Your ability to understand a passage, its structure, and what the author is really saying. At the sub-505 level, accuracy and speed both matter.
Common trap
Answering from memory or outside knowledge instead of strictly from the passage.
Details
Difficulty
sub-505
Type
RC
Category