All Questions
Tagged with newtonian-gravity classical-mechanics
112
questions
0
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1
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68
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Confusing about orbital speed [closed]
The Earth's distance from the Sun varies from $\ R_p=\ $ 1.471x$\ 10^8\ $km to $\ R_a=\ $ 1.521x$\ 10^8\ $km during the year. Determine the difference in the Earth-Sun system kinetic energy.
I have ...
- 3
1
vote
2
answers
85
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Are the models describing the classical gravitational and electric fields mathematically equivalent?
In other words if I have a static point mass and a static point charge, we model them as having a scalar potential field surrounding them: $$V(r)\propto\frac{1}{r}$$ and their vector fields are ...
- 6,963
2
votes
2
answers
2k
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Why does Friction act Parallel to the Surface (Microscopic Level)?
If we assume an object (blue layer) sliding towards the right across a surface (black layer). According to Newton's 3rd Law, the frictional force would act to the left (resisting the object's relative ...
user226894
12
votes
2
answers
1k
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Why is it that forces like gravity and electricity (approximately) basically act between pairs of bodies only?
In classical mechanics, with the limit of little movement (so no relativity, waves, and/or "magnetic" effects), we can see that gravitation and electricity can both be described as "two-body" forces, ...
- 20.6k
1
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90
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Reference Frame conceptual confusion
I am getting confused as to why a ball still feels gravity when inside a moving car. The point of a reference frame is to reinterpret all the forces acting on a particle in one frame only. Hence all ...
4
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86
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Apple shape with no gravity [closed]
Would the shape of an apple change if it grew with no gravity?
I would expect it having a slightly narrower and deeper dent where the stem is attached but I cannot quite figure out how to estimate ...
- 1,874
0
votes
1
answer
94
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Velocity of an orbiting body
The velocity of an orbiting body is given by:
$$v = \sqrt{\frac{Gm}{r}}$$
I was trying to derive this formula earlier but I was struggling with incorporating $G$ into my derivation.
I tried looking ...
- 324
1
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108
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If gravitation force varied with $r^{-3}$ instead of $r^{-2}$ what would happen to Kepler's laws [duplicate]
2nd law wouldn't change as it is LCAM. 3rd Law would change. But I'm confused about first law. Does any body under influence of any central force move in an ellipse?Can anyone give a simple proof/...
- 109
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433
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Motion of the center of mass of rigid bodies in space
For the classic two body problem, I know that the motion of the center of mass is a straight line (with respect to an inertial frame), provided that the bodies are considered as point particles.
Now ...
user84108
0
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2k
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Distance between centre of earth and centre of moon
So here's the question:
Calculate the approximate distance between the centre of the Earth and the centre of
the moon. You may use the mass of the Earth as $6\times10^{24} kg$ and $G = 6.67\times10^{-...
-2
votes
1
answer
115
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Spirals in newtonian celestial mechanics?
I know Kepler's laws, Newton's laws, and that conic sections are the trajectories of noncolliding two point masses. But I wonder about a point mass A eventually colliding with point mass B.
In ...
- 926
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482
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Connection between Kepler Problem and Harmonic Oscillator
Background. Take the Kepler Lagrangian as
$L^K = \frac{1}{2}\dot{q}_i\dot{q}_i + \frac{k}{q}$,
and the Lagrangian for the isotropic harmonic oscillator as
$L^H = \frac{1}{2}\dot{q}_i\dot{q}_i - \...
- 21
15
votes
2
answers
512
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Regularization: What is so special about the Coulomb/Newtonian and harmonic potential?
I wanted to know if the procedure for regularization of the Coulomb potential outlined in Celletti (2003): Basics of regularization theory could be generalized to arbitrary polynomial potentials. So ...
- 9,910
1
vote
2
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381
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Deformation of a self-gravitating sphere from two forces
I have a fluid sphere (say a gas or a liquid of uniform density, under its own gravity) on which forces is applied to its surface. I would like to find its approximate shape (most probably an oblate ...
- 7,592
15
votes
2
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6k
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Conservative central force and stable orbits
I saw a question a few days ago which referred to Bertrand's theorem. So, I now know that stable, closed orbits only occur when the potential function is $\frac{-k}{r}$ or $\tfrac{1}{2}kr^2$.
If ...
- 2,075