All Questions
Tagged with newtonian-gravity conventions
19
questions
43
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Why is gravitational potential energy negative, and what does that mean?
I usually think of gravitational potential energy as representing just what it sounds like: the energy that we could potentially gain, using gravity. However, the equation for it (derived by ...
15
votes
5
answers
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Near Earth vs Newtonian gravitational potential
Newton's Law of Universal Gravitation tells us that the potential energy of object in a gravitational field is $$U ~=~ -\frac{GMm}{r}.\tag{1}$$
The experimentally verified near-Earth gravitational ...
- 343
6
votes
2
answers
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Work done against gravity [closed]
The work done against gravity is $mgh$, well at least that's what my textbook says.
I have a question:
I can apply a force say 50N, so total work done = $mgh + mah$. Where $ma$ = Force.
But the truth ...
6
votes
4
answers
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Potential energy sign conventions
Almost every book on physics that I read have some weird and non-clear explanations regarding the potential energy. Ok, I do understand that if we integrate a force over some path, we'll get a ...
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8
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6
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Why is potential energy negative when orbiting in a gravitational field?
I had to do a problem, and part of it was to find the mechanical energy of satellite orbiting around mars, and I had all of the information I needed. I thought the total mechanical energy would be the ...
- 2,889
3
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3
answers
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What is meant by 'Gravitational Potential Energy of a System'?
'Gravitational potential energy' is defined as: 'energy an object possesses because of its position in a gravitational field'.
Consider two planets of masses $M$ and $m$ at a distance from $r$ of each ...
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1
vote
1
answer
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Why gravitational potential is negative, as displacement and force are in the same direction?
Gravitational potential at a point in a gravitational field is defined as work done per unit mass in bringing a small test mass from infinity to the point.
I know that:
By integration, we find that ...
- 65
0
votes
3
answers
988
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Why is the gravitational potential energy defined as negative? [duplicate]
It is said that since work is done by the gravitational potential itself , so at a finite distance the gravitational potential energy of the body is negative.
Could someone explain why?
6
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5
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Why the gravitational potential energy at infinity is zero?
If an object is taken from earth's surface to infinity, it's gravitational potential energy becomes zero (always taken as zero), but it doesn't make any sense as energy can never be destroyed so where ...
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1
vote
2
answers
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Confusion regarding the concepts and derivation of Hydrostatic Equilibrium for a star
First and foremost I am sorry for this; in order to make the questions clear I must first upload the lecture notes from my institution $^\zeta$ for the derivation of Hydrostatic Equilibrium:
$^\...
- 2,470
0
votes
3
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How do I get the negative sign in the expression for Gravitational Potential Energy?
From universal law of gravitation, gravitational force exerted on a body of mass m by another body of mass M is
$$ \mathbf F = \frac{GMm}{x^2} $$
where x is the distance between the ...
0
votes
2
answers
708
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Integrating a dot product gives wrong sign for work done [duplicate]
Consider a point mass which creates a gravitational field. The gravitational force pulls a 'test mass' towards the point mass. Since the displacement and gravitational force are in the same direction, ...
2
votes
2
answers
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Confusion with $F=-\nabla V$, $F$ conservative
I am rather confused by the relationship $F=-\nabla V$.
If a pen drops from a height it loses potential energy so $\nabla V$ is negative. From the above equation this means that the gravitational ...
- 195
2
votes
2
answers
1k
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Signs in proof of gravitation potential energy (GPE)
Proof of gravitational potential energy.
Work done by gravity in bringing mass from infinity to a distance of $r$ between masses.
When we use the integration formula and arrive at the answer we ...
- 49
2
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2
answers
10k
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Work Done by Gravitational Force
[Bit a long question]
Here in this question, I need to know clear my doubts on Gravity, more precisely Work done by a Conservative Force(here, gravitational force).
Ok, suppose there is an object ...
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