All Questions
Tagged with newtonian-gravity angular-momentum
110
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Doubt on conservation of angular momentum for Kepler's laws
Just before proving Kepler's laws, my Professor claimed that if $\vec{F}$ is a central force with center $O$ and it is the only force acting on a point $P$, then the trajectory of $P$ is a curve plane....
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Gravitational collapse - proof that energy dissipation is required?
As an undergraduate, I took a short course on astrophysics, where I encountered the Jeans mass. This is the critical mass for a spherical cloud of interstellar gas above which the cloud is predicted ...
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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 ...
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Attraction between dark matter
Why does dark matter not attract other dark matter in space, and form a giant structure?
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Why are there so many objects perfectly orbiting each other? Isn't it infinitely more likely that two random objects crash/fly apart?
If, in free space, I throw two objects towards each other, they can either miss each other and fly apart (if the velocity is enough and there's not enough gravitational attraction between them), or ...
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Conservation of Angular Momentum in Elliptical Orbit: simple yet confusing [closed]
Problem
A satellite orbit is to change from elliptical to circular with radius $2 R$. The satellite is at point $A$ on the elliptical orbit as shown in the figure. Determine the speed of the ...
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1
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In orbital mechanics why is the angular momentum $\bf{h}$ constant?
In the context of an object moving under the influence of gravity, in Bate, Mueller, White it says, sect. 1.4.2
The expression $\bf{r} \times \bf{v}$ which must be a constant of the motion is simply ...
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Doubt regarding derivation of general expression of angular momentum of circular orbits [closed]
The Newtonian angular momentum $J$ of a circular orbit for a gravitational potential $\Phi$ is given by the relation (eqn. 10 of this paper)
$$J=\left(r^3\dfrac{d\Phi}{dr}\right)^{1/2}.$$
For the ...
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3
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802
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Angular Momentum vs. Force Due to Gravity
I'm getting my feet wet with orbital mechanics and have a very basic question. Kepler's 2nd Law shows that 2 objects in an elliptical orbit sweep out equal areas in equal time, implying objects ...
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1
answer
184
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Why Saturn's rings lie in the same plane? [duplicate]
This is Saturn.
In every picture of Saturn, we can see that her rings are arranged in a perfect 2-d plane.
So the question I ask is simple, why are they arranged so? Why aren't the rings arranged in ...
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Why does the energy for a circular orbit not lie in the pit of the effective potential?
According to the well-known graph of the effective potential, it is clear that the body enters orbit only starting with some energy and at this energy the orbit goes round. In an experiment in the ...
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Questions regarding an Olympiad problem for perturbational solutions of the three-body problem
This theoretical problem on the International Physics Olympiad talks about the three-body problem with respect to LISA. In one of their solutions to the problem:
Consider the case $M=m$. If $\mu$ is ...
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8
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150
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Can a drop of water be set in rotational motion by rotating mass around it?
We are in empty space and see a spherical drop of water. Around the drop we have placed a massive shell with uniform density. The drop is positioned at the center. Then we set the shell in rotational ...
0
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1
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Two final velocities for a mass launched from Earth
i'm trying to find the final velocity of a mass that is launched vertically from the earth, only considering the gravitational force.
My first attempt was with angular momentum:
$r$ is the distance ...
- 3
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5
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How does gravity make us rotate about the rotation axis of earth?
A body at the surface of earth experiences at least two obvious forces - gravity and its weight (normal of the surface). Both of these forces act on the radial axis that goes through the center of ...
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