All Questions
26
questions
1
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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
-4
votes
2
answers
98
views
Well I dont know, what you want? [closed]
When you calculate the gravitational force $F_G = G \cdot\frac{m\cdot M}{r^2}$.
Is this equation precise for relativistic big masses, given that $m$ and $M$ do not and can not move?
If not is there an ...
- 1
1
vote
1
answer
87
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Does weightlessness make no difference to free fall?
I looked up a lot of articles and questions about free fall motion and weightlessness. And I know there are a lot of similar questions.
In conclusion, I understand that there is no way to distinguish ...
- 305
0
votes
0
answers
52
views
Gravity, orbiting bodies and Newton’s second law of motion [duplicate]
As I understand it an object travelling in a circular motion is undergoing a centripetal ‘force’. As Newton’s second law of motion, put in simple terms states that a moving object will tend to ...
- 719
0
votes
2
answers
157
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Does a hot object have more gravity than a cold object - conflicting views [closed]
In this similar question the answer says that because of relativity e=mc^2 a hot object has greater mass/energy therefore has greater gravity than a cold object.
But:
In Experiment on the Relationship ...
- 4,783
0
votes
3
answers
95
views
How can weight be equal in the equivalence principle?
According to Einstein, weight will be the same as here in earth in a rocket going at 1G far from gravity fields. If we propulse an object here it will feel two forces, F=mg and F=ma of the thrust, but ...
user189508
0
votes
0
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29
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Delta_V from gravitational interaction at relativistic speeds
This question was prompted by a separate question about planetary encounters. The small delta_V from a high-speed near miss of two equal bodies was calculated as GM/dv, where M is the mass of either ...
- 2,403
1
vote
1
answer
58
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If gravitational field is not real, then am I gaining energy?
I don’t know much about General Theory Of Relativity but I have heard that it does not consider gravitational fields like Newtonian Mechanics.
If an object were to be free falling, then according to ...
- 11
1
vote
1
answer
766
views
Formula of black hole gravitational sphere of influence
Well,
I want to derive the formula
$$ r = \frac{GM}{\sigma^{2}} $$
which happens to be the radius of the gravitational sphere of influence of a supermassive black hole inside a galaxy. How can I do ...
- 55
4
votes
7
answers
2k
views
Is this a way to distinguish between a gravitational field and an accelerated rocket?
It will be so great if someone help me with this, and try to understand what's my point and what I am trying to say. I have asked a question few days ago, and it was closed because, apparently it wasn'...
user255961
22
votes
5
answers
7k
views
What helped Einstein to provide a more accurate description of gravity than Newton?
Newton's explanation of gravity as an attractive force seems to have been superseded by Einstein's explanation of gravity as warping of space-time. Was there any advances in math and science that was ...
- 431
2
votes
2
answers
129
views
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
-2
votes
2
answers
110
views
With the advent of General Relativity, do Newtonian Mechanics really describe the universe correctly? [duplicate]
Do concepts in Newtonian Mechanics such as Normal force, etc. still hold true?
I don’t mean if you use newtonian mechanics, will it still chunk out the correct computation.
What i mean is that does ...
- 123
1
vote
1
answer
170
views
Question about general relativity.
I know from my study of Newtonian mechanics that the force acting on any particle in the vicinity of any object is mass of the particle times the gravitational field at that point. My question is that ...
- 262
0
votes
2
answers
765
views
General Relativity, Newtonian Mechanics and Gravity
Gravity is considered to be the curvature of spacetime by Einstein and a force by Newton. So are both notions equally correct or Einstein's perspective completely replaced Newton's thinking?
- 11