All Questions
6
questions
0
votes
2
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180
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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
0
votes
1
answer
163
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Circular velocity vector on the surface of spherical potential (gravity)
So, I would like to integrate paths of particles on circular velocity on the surface of a sphere (due to some potential, i.e. gravity).
The problem is to fix the two angular velocities $\dot \theta $ ...
- 1
0
votes
1
answer
71
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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
7
votes
2
answers
1k
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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
2
votes
2
answers
129
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Is the gravitational potential a measurable physical quantity or an artifact of warped measures?
The Euler-Lagrange conditions for stationary points of $$L=m/2 v(\mathbf{\dot{x}})^2-U(\mathbf{x})$$
($m$ is mass, $v()$ is velocity, $U()$ is the scalar potential, and the boldfaced arguments of ...
- 1,517
1
vote
1
answer
37
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n-body problem: at least one point mass approaches spatial infinity as t -> ∞
given an n-body problem $n>1$ and $T+U>0$, I have to prove that at least one of these n point masses approaches spatial infinity as time goes ad infinitum.
I was given the advice to first show ...
