All Questions
Tagged with newtonian-gravity gravity
83
questions
39
votes
5
answers
34k
views
Would you be weightless at the center of the Earth?
If you could travel to the center of the Earth (or any planet), would you be weightless there?
- 543
34
votes
4
answers
8k
views
How can we recover the Newtonian gravitational potential from the metric of general relativity?
The Newtonian description of gravity can be formulated in terms of a potential function $\phi$ whose partial derivatives give the acceleration:
$$\frac{d^2\vec{x}}{dt^2}=\vec{g}=-\vec{\nabla}\phi(x)=\...
- 1,406
92
votes
7
answers
13k
views
If dark matter only interacts with gravity, why doesn't it all clump together in a single point?
I'm a complete layperson. As I understand, dark matter theoretically only interacts with the gravitational force, and doesn't interact with the other three fundamental forces: weak nuclear force, ...
- 1,619
22
votes
7
answers
5k
views
The distance square in the Newton's law of universal gravitation is really a square?
When I was in the university (in the late 90s, circa 1995) I was told there had been research investigating the $2$ (the square of distance) in the Newton's law of universal gravitation.
$$F=G\frac{...
12
votes
4
answers
6k
views
Can gravity be shielded, like electromagnetism? [duplicate]
If I remember well, they said that it can't, but I do not know why.
Yes, I meant if gravity can be shielded using something like a Faraday cage
(or something else?).
Thank you.
- 1,436
9
votes
2
answers
2k
views
Gravity in 2+1D spacetime and inverse linear law
In our 3+1D universe, gravity obeys the inverse square law. In a 4+1D universe, gravity would be expected to obey the inverse cube law et cetera.
In a 2+1D universe, one would similarly expect gravity ...
- 281
13
votes
4
answers
7k
views
Can a black hole be explained by Newtonian gravity?
In the simple explanation that a black hole appears when a big star
collapses under missing internal pressure and huge gravity, I can't see
any need to invoke relativity. Is this correct?
- 1,436
10
votes
4
answers
14k
views
Similarity between the Coulomb force and Newton's gravitational force
Coulomb force and gravitational force has the same governing equation. So they should be same in nature. A moving electric charge creates magnetic field, so a moving mass should create some force ...
- 1,975
27
votes
10
answers
13k
views
How does Newtonian gravitation conflict with special relativity?
In the Wikipedia article Classical Field Theory (Gravitation), it says
After Newtonian gravitation was found to be inconsistent with special relativity, . . .
I don't see how Newtonian gravitation ...
- 8,540
7
votes
3
answers
2k
views
Using 2D position, velocity, and mass to determine the parametric position equations for an orbiting body
I have a gravity-related question. I am programming an orbit simulator. I have everything up and running, but I would like to render the smaller body's orbital path (the larger body is fixed). To do ...
- 173
25
votes
2
answers
2k
views
How do spiral arms form?
Why aren't all spinning galaxies shaped as discs as my young mind would expect? I understand how the innermost parts of a galaxy spin faster than the outer parts, and that could explain why some ...
- 1,127
20
votes
7
answers
7k
views
Is Newton's Law of Gravity consistent with General Relativity?
By 'Newton's Law of Gravity', I am referring to
The magnitude of the force of gravity is proportional to the product of the mass of the two objects and inversely proportional to their distance ...
- 6,000
8
votes
2
answers
3k
views
How general relativity gets to an inverse-square law [duplicate]
I understand that a general interpretation of the $1/r^2$ interactions is that virtual particles are exchanged, and to conserve their flux through spheres of different radii, one must assume the ...
- 4,256
8
votes
5
answers
11k
views
What happens with the force of gravity when the distance between two objects is 0?
so I had my first approximation to the gravity equation
\begin{equation}
F=GmM/r^2
\end{equation}
and some questions arose that my teacher couldnt respond:
if r approximates to 0 with mM being ...
- 207
2
votes
3
answers
6k
views
Why is Gravitational force proportional to the masses?.
We know that two mass particles attract each other with a force
$$F~=~\frac{G M_1 M_2}{r^2}.$$
But what is the reason behind that? Why does this happen?
- 183