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Ch. 06 - Gravitation and Newton's Synthesis
Giancoli Douglas - Physics for Scientists and Engineers 5th edition
Giancoli Douglas5th editionPhysics for Scientists and EngineersISBN: 9780137488179당신이 사용하는 게 아니라요?교과서 변경
6장, 문제 25b

The value of g is altered by approximately Δg2gΔrrE\(\Delta\) g\(\thickapprox\)-2g\(\frac{\Delta r}{r_{E}\)} at a height ∆r above the Earth’s surface, where rE is the radius of the Earth, as long as ∆r ≪ rE. What is the meaning of the minus sign in this relation?

검증된 단계별 안내
1
The given relation, ∆g ≈ -2g ∆r/r_E, describes how the acceleration due to gravity (g) changes with a small height (∆r) above the Earth's surface, assuming ∆r is much smaller than the Earth's radius (r_E). The minus sign in this equation indicates the direction of the change in g relative to the increase in height.
To understand the minus sign, recall that the acceleration due to gravity decreases as we move farther from the Earth's surface. This is because gravity weakens with distance according to the inverse-square law.
In this context, the minus sign signifies that as ∆r (the height above the Earth's surface) increases, the value of ∆g (the change in gravity) becomes negative, meaning g decreases.
Mathematically, the negative sign reflects the fact that the derivative of g with respect to r (distance from the Earth's center) is negative. This aligns with the physical reality that gravity diminishes with increasing distance.
Thus, the minus sign in the relation ∆g ≈ -2g ∆r/r_E conveys the inverse relationship between the change in gravity and the increase in height above the Earth's surface.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
2m
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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Gravitational Acceleration (g)

Gravitational acceleration, denoted as 'g', is the acceleration experienced by an object due to the gravitational force exerted by a massive body, such as Earth. Near the Earth's surface, this value is approximately 9.81 m/s². The value of 'g' decreases with increasing height above the Earth's surface, which is described by the formula provided in the question.
추천 영상:
07:32
Weight Force & Gravitational Acceleration

Height Above Earth's Surface (∆r)

The term ∆r represents a small change in height above the Earth's surface. In the context of the question, it indicates how much higher an object is compared to the Earth's surface. The relationship between ∆g and ∆r shows that as one moves away from the Earth, the gravitational acceleration decreases, which is significant for understanding how gravity varies with altitude.
추천 영상:
9:26
Gravitational Force Inside the Earth

Negative Sign in the Relation

The negative sign in the relation ∆g ≈ -2g ∆r/r_E indicates that the change in gravitational acceleration (∆g) is a decrease as height (∆r) increases. This means that as you move away from the Earth's surface, the gravitational pull becomes weaker, which is a fundamental concept in gravitational physics. The negative sign emphasizes the inverse relationship between height and gravitational acceleration.
추천 영상:
08:55
Net Torque & Sign of Torque