All Questions
Tagged with newtonian-gravity gravity
404
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How much time does it take for an object to fall from space? [closed]
Let's say there's an object of mass $m$ in space, $h$ meters away from the surface of the Earth. $h$ is large enough that $g$ cannot be assumed to be constant. The acceleration varies according to ...
- 119
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28
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Better equations for modeling and simulating a halo orbit?
I'm trying to model a halo orbit at low altitude (10m from surface). The satellite is using propulsion to trace the circular halo path. It looks like this "from the top" (the blue ball is ...
- 231
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When is it appropriate to say Newtonian gravity is a force? When is it not appropiate? [closed]
Please help me understand the notion of force when it is applied to Newtonian gravity. From my understanding forces in physics involve interactions with at least 2 objects and can cause an ...
- 431
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Dual of Newtonian gravitational field
In the static state, the laws of Newtonian gravity and Coulomb force have exactly same formulas,
$$F = K \frac{A_1A_2}{r^2}.$$
In the electrical case, moving materials produce a field, say a dual ...
- 1,409
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Einstein's equation of gravitation field [duplicate]
I'm looking for the reason why there is the number eight $8$ at the r.h.s. of EI:
$$R_{\mu\nu}-\frac{1}{2}Rg_{\mu\nu}=\frac{8\pi G}{c^2}T_{\mu\nu}.$$
My attempt was to take the limit of this equation ...
- 255
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49
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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
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How does gravity act and propagate in a 2+1D universe?—Newtonian versus general relativity
In a hypothetical 2+1D universe:
if we apply the Newtonian concept of gravity, we might expect that the gravitational force between two mass points with a distance of $r$ would diminish linearly with ...
- 618
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105
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References on Newton-Cartan Gravity
I'm interested in learning a bit about Newton-Cartan gravity, and I would like some references on the topic. I am already familiar with differential geometry and general relativity, so those could be ...
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2
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Understanding conservation of angular momentum in relation with rotating objects
Conservation of angular momentum says that the angular momentum of a closed system will not change if there is no external torque applied to the system. For example, let's take the example of a ...
- 665
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Physical relevance of the $ij$ components of the Einstein field equations in the Newtonian limit
In the weak field limit of general relativity (with matter described by a perfect fluid consisting only of dust), we have the following correspondences:
$00$-component of the Einstein field equations ...
- 830
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If most of an atom's mass comes from binding energy, why did people think that anti-hydrogen could fall up if antimatter had negative mass?
Antimatter isn't bound by anti-energy, so doesn't that mean that even if elementary antimatter particles had negative mass, the total mass of an anti-atom would still be overwhelmingly positive?
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Negative Energy and Gravity
Why do many science communicators say that negative masses fall upwards? Is it the same in the physics literature that they say that negative masses fall upwards?
In general relativity, things don't ...
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Newtonian approximation for the tidal forces at the event horizon of a black hole
I'm currently working on a problem where I have to calculate the tidal forces a person experiences if their feet touches the Schwartzschild radius and their head is $1.8m$ elevated above the ...
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Trying to understand Gravitational Field
I have learned that gravitational potential is defined as the amount of work done on bringing the mass from infinity to distance r.
But what does that infinity signify in the definition, I mean like ...
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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 ...
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