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PHY 101 PHY 101 Past Questions Objective Question
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Question

Kepler's second law (law of equal areas) is a consequence of the fact that:
Options
A The gravitational force is an inverse square law.
B The gravitational force is a central force, exerting no torque on the planet.
Correct Answer
C The orbits are elliptical.
D The mass of the Sun is much greater than the mass of the planets.
Correct Answer

Option B is the correct answer.

Detailed Explanation

shows that the rate of sweeping area ΔA/Δt = L/(2m), where L is angular momentum. Because the gravitational force is radial (a central force), the torque about the Sun is zero, so angular momentum L is constant. Therefore, ΔA/Δt is constant.

Hint

Conservation of which quantity leads to constant areal velocity?

Question Info

Course: PHY 101
Topic: PHY 101 Past Questions
Type: Objective
Difficulty: Not specified
Question 553 of 1250
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