All Questions
13
questions
0
votes
2
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51
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Gravitational potential due to arbitrary shape
Outside the uniform sphere, the potential is expressed as if all the masses are concentrated in the center of the sphere.
Is it also true for arbitrary shape?
That is, outside any body, is potential ...
- 51
0
votes
2
answers
181
views
How much kinetic energy would a star in a galaxy have if it fell to the center?
I want to calculate the speed, or equivalently, the kinetic energy of a star, if it had no rotational speed and fell from a given radius to the center of the galaxy.
I assume Newton's shell theorem ...
- 476
4
votes
4
answers
525
views
Interpretation of gravitational waves
A wave has peaks and valleys. I can think of a sine wave as a wave with peaks and valleys.
Now, if gravity is a wave, can we say that gravity would have peaks and valleys, with the valley becoming ...
- 1,023
0
votes
2
answers
729
views
What is the gravitational potential of a homogeneous sphere? [closed]
I am studying gravitational potentials from the book Galactic Dynamics by James Binney and Scott Tremaine. They provide the equation from where the potential of a spherical system is to be derived as:
...
- 197
0
votes
1
answer
71
views
The gravitational potential at the center of a solid ball (confusion)
I came across this question during my physics class. Suppose we have a solid, spherical planet with mass $M$ radius $R$ s.t. the density of this planet is uniform everywhere, then what is the ...
- 115
2
votes
1
answer
192
views
Why is Principle of superposition not oftenly used for gravitational potential?
We talk a lot about this principle for electric potential at point by many charges but not for gravitational potential by other masses around it, why?
1
vote
1
answer
429
views
Gravitational potential due to uniform ring [closed]
So i want to find the Gravitational potential caused by a uniform ring with radius $R$ at any point in space. I know the solution of the field should not have any dependence on the azimuthial angle ...
1
vote
2
answers
301
views
Newton's Universal Law of Gravitation doubt
The Universal Law of Gravitation states that the module of the force, $F$ is
$$F = \frac{GmM}{r^2},$$
where $m$ and $M$ are the mass of the two objects and $r$ is the distance between the two objects....
- 179
1
vote
2
answers
3k
views
Direction of gravitational field given equipotential lines
I've attached the question as an image below as it's a graphical question.
It simply states:
"The diagram shows equipotential lines near a group of asteroids. Which arrow shows the direction of the ...
- 17
7
votes
2
answers
1k
views
What is the physical reason for why gravitational potential (or electrical potential) due to two masses at a point can simply be added algebraically?
The simple explanation that textbooks and the internet say is that "gravitional potential is a scalar quantity hence can be added algebraically".
However, I'm not sure if it is that simple. Take for ...
- 797
0
votes
1
answer
479
views
Question on Escape Speed derivation
Reading lecture notes, I have some questions on this derivation's assumptions.
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It must gain GMEm/RE in Gravitational Potential Energy (where ME is mass of the earth and RE is radius of the Earth)? ...
- 3,200
2
votes
1
answer
620
views
Gravitational Multipole Moments
I'm trying to write the gravitational potential of two masses $m_1$ and $m_2$ using the multipolar expansion of the potential:
$$V = G\sum\frac{1}{r^{n+1}}\int r'^n P_n(\cos \theta) \rho(r') dV'$$
I ...
- 113
2
votes
1
answer
366
views
First integral of the Kepler problem
Consider the motions of a bounded particle which is under the influence of the
gravitional interaction of a second particle fixed at the origin
$$
\ddot q = -\nabla V(q)
$$
where $V(q) = - \frac{\mu}...
- 165