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 statements best reflect the most logical and rational inferences that can be made from the passage?

1.A more massive double-star system will exhibit a shorter orbital period if the distance between the stars is similar to that of a less massive system.

2.The gravitational force, like the tension in the string, is continuously responsible for maintaining the stars' orbital motion.

Select the correct answer using the code given below:

(a)1 only

(b)2 only

(c)Both 1 and 2

(d)Neither 1 nor 2

Question

Astronomers use an analogous procedure to &ldquo;weigh&rdquo; 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&rsquo; combined mass, according to Newton&rsquo;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 statements best reflect the most logical and rational inferences that can be made from the passage?

1.A more massive double-star system will exhibit a shorter orbital period if the distance between the stars is similar to that of a less massive system.
 

2.The gravitational force, like the tension in the string, is continuously responsible for maintaining the stars' orbital motion.

Select the correct answer using the code given below:

(a)1 only

(b)2 only

(c)Both 1 and 2

(d)Neither 1 nor 2

ONLiNE UPSC · Accepted Answer

Statement 1 is correct: The passage states the attractive force is proportional to the combined mass. A stronger force due to greater mass would lead to faster orbital speeds to maintain a stable orbit at a similar distance. Faster speeds at a similar distance result in a shorter orbital period.

Statement 2 is correct: A string under tension provides a continuous inward pull (centripetal force) that can keep an object moving in a circle. The gravitational force between the stars similarly acts as a continuous attractive force that keeps them in orbit around each other. The analogy or similarity helps visualize this "restraining force."

Physics

Gravitation

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