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1 vote
1 answer
29 views

Describe the decrease in potential energy if two forces are acting on it one conservative which is greater than other applied by us in opposite dirn [closed]

So imagine this situation. An object is experiencing two forces, one due to gravity in downward direction and other applied by us in upward direction such that our force is less than gravitational ...
Vikas Asdev's user avatar
9 votes
3 answers
2k views

Contradiction in negative mass interactions according to GR

I quote Sabine Hossenfelder: Gravitation is a spin-2 interaction. It is straightforward to see that this means that like charges attract and unlike charges repel. The charge of gravity is the mass. ...
Manuel's user avatar
  • 476
1 vote
0 answers
51 views

What is the difference between GPE and gravitational self energy in GR?

What is the difference between gravitational potential energy and gravitational self energy in General Relativity? Are they both the same in Newtonian gravity?
Manuel's user avatar
  • 476
0 votes
1 answer
39 views

How a force that is always perpendicular to velocity can change the kinetic energy when another force is acting oppposite to velocity? [closed]

When a satellite is revolving around a planet with an orbital velocity in presence of air resistance, the satellite's Kinetic Energy keeps on increasing as it falls down. The resistive force is trying ...
Motivix's user avatar
  • 101
4 votes
4 answers
524 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 ...
Angela's user avatar
  • 1,023
1 vote
2 answers
189 views

What is the gravitational field intensity of a uniformly distributed mass content in Newtonian gravity?

In an infinite universe composed of single point masses which can be simplified as a uniformly distributed mass density, what is the equation for the gravitational field intensity in Newtonian gravity?...
Manuel's user avatar
  • 476
2 votes
1 answer
267 views

How to calculate the period of non-circular orbits?

How to calculate the period of non-circular orbits? By conservation of mechanical energy: $$ E = -\frac{GMm}{r} + \frac{1}{2}\mu \left ( \dot{r}^2 + r^2 \dot{\theta}^2 \right ) $$ By the conservation ...
Álvaro Rodrigo's user avatar
0 votes
1 answer
44 views

How is when an object moves gravity not effect it ? As Einstein sais?

Experiment: *a water bottle with a hole . Water is falling from the hole when the bottle is in rest . When the bottle is released and falls , water stops falling as gravity is not doing effect on it . ...
Rinku Das's user avatar
0 votes
1 answer
118 views

Is there an equation that is quick to use that calculates gravity around black holes?

Is there an equation the can calculate gravity around black holes but is less time consuming than EFE? I want to find an equation that is simpler/faster than Einstein's Field Equations but can still ...
Chance Evans's user avatar
2 votes
1 answer
55 views

Does MOND respect linear superposition of gravitational field intensities?

Does Milgrom's MOND respect linear superposition of gravitational field intensities as Newtonian gravity does?
Manuel's user avatar
  • 476
0 votes
2 answers
119 views

Since when did inertial mass and gravitional mass became equal?

If we think about inertial mass and gravitational mass as independent concepts and develop physics then we would know after a while they are only propotional (by precision we have by now). but it seem ...
moshtaba's user avatar
  • 1,409
1 vote
2 answers
139 views

Star with quadrupole in binary system violates Newton's 3th law?

Suppose that, in a binary system of two stars, the star A (and only the star A) has a non-zero quadrupole moment $Q_A$. Then, the star B feels the usual gravity force plus an additional force, ...
gravitone123's user avatar
1 vote
3 answers
140 views

Do objects with non-uniform shapes and mass distributions rotate as a result of gravitational attraction?

I was thinking about orbital mechanics this morning and a question arose: do objects with non-uniform shapes and mass distributions rotate as a result of gravitational attraction? Thinking through the ...
Polynomial's user avatar
4 votes
2 answers
695 views

General relativity when can we approximate to Newtonian gravity?

Lets consider this scenario in deep void of space where other curvatures of large objects are negligible in this case and we bring 2 objects lets say $A$ and $B$. We give it a force slightly lower ...
Razz's user avatar
  • 441
3 votes
3 answers
84 views

Newton's approximation of 2+1D gravity

I learnt that the curvature tensor in 2+1D spacetime is zero in vacuum. How is it possible to come from there to the Newton's theory in 2D + time, where I guess, the gravitational force law is still ...
Frederic Thomas's user avatar

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