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How to calculate the offset of a full moon and the opposite point of the sun?

The first calculation, based on the $5.14^\circ$ that we can look up (with some reasonably small parallax correction) seems OK. As for the second computation, even without explicit check in Stellarium,...
Jos Bergervoet's user avatar
0 votes

Trajectories of projectile based on different speeds of projection

According to classical dynamics (Marion and Thornton, Central Force motion chapter), the eccentricity $\epsilon$ of the trajectory of two bodies in central motion is given by: $\epsilon = \sqrt{1 + \...
cconsta1's user avatar
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0 votes

Pseudo Orbital motion only due to Coriolis force

In the case you are asking about: Describing the motion relative to the rotating coordinate system requires more than the coriolis term; the centrifugal term is necessary too. In total three terms are ...
Cleonis's user avatar
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1 vote

Pseudo Orbital motion only due to Coriolis force

This is certainly possible. However, it's much easier to visualize what happens by thinking about the inertial frame first. Specifically, if an observer launches a projectile "vertically upwards&...
Michael Seifert's user avatar
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Pseudo Orbital motion only due to Coriolis force

How to calculate escape velocity actually you can look at escape velocity
sayed's user avatar
  • 1
3 votes

Would the Moon move away if the Earth were frozen with no liquid tide?

Am I right that the moon's altitude increase would cease if the Earth didn't have liquid oceans? It should certainly be less, though it is difficult to test. It would not stop entirely. The ...
BowlOfRed's user avatar
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0 votes

What changes the velocity perpendicular to radius in an elliptical orbit?

Suppose on Monday I decide that my favorite planet is Mars. Then my favorite planet is moving at 24 km/s. Suppose on Tuesday I change my mind and decide that my favorite planet is Mercury. Now my ...
Acccumulation's user avatar
2 votes

What changes the velocity perpendicular to radius in an elliptical orbit?

Why does $v_p$ change when there is apparently no force in that direction? Roughly, because polar coördinates are tricky. It helps to have some concrete examples and the answer from JiK gives a good ...
CR Drost's user avatar
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11 votes

What changes the velocity perpendicular to radius in an elliptical orbit?

A simple example to specifically point out your error here. In general $v_p$ can change even if there's no force at all! So it seems to me that $v_p$ should keep constant as there is no force acting ...
JiK's user avatar
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5 votes

What changes the velocity perpendicular to radius in an elliptical orbit?

System: Planet $B$ $\dots$ kinetic energy conserves for a planet in an elliptical orbit is not a correct statement. The force $F$ on body $B$ due to body $A$ is central and has a component in the ...
Farcher's user avatar
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7 votes

What changes the velocity perpendicular to radius in an elliptical orbit?

You can prove that $\mathbf{L}$ is constant performing time derivative and remembering that the force is central, $$m \ddot{\mathbf{r}} = m \dot{\mathbf{v}}= - G\frac{M \, m}{r^3}\mathbf{r}$$ i.e. ...
basics's user avatar
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2 votes

What changes the velocity perpendicular to radius in an elliptical orbit?

$v$, the velocity vector of the body, is not constant in magnitude because in a generic elliptic orbit it is not perpendicular to the radius. It is, however, in circular orbit which indeed has ...
ebenezer's user avatar
2 votes

What changes the velocity perpendicular to radius in an elliptical orbit?

Angular momentum is a conserved vector, by your calculation, it is composed of two potential variable: $\vec{L} = \vec{r} \times m\vec{v}_p$, $m$ is a constant. In an elliptical orbit, $\vec{r}$ is ...
Polaris5744's user avatar
0 votes

Escape Velocity from Moon to escape Earth-Moon System

This is a problem utilizing a rotating coordinate system because the earth and the moon rotate about the center of mass of this two-body system known as the barycenter. The center of mass of the ...
Chris K's user avatar
1 vote
Accepted

Find eccentricity of orbit given the velocity and the semi-major axis

Relating Average Velocity to Orbital Period: $$T^2 = \frac{4 \pi^2 a^3}{G M}$$ $$v = \frac{2 \pi a}{T}$$ Combining the Equations: $$v = \frac{2 \pi a}{\sqrt{\frac{4 \pi^2 a^3}{G M}}} = \frac{2 \pi a}{...
Sid N's user avatar
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1 vote
Accepted

Deflecting a lunar mass with consecutive nuclear explosions

This could not work. Not even close. Let's start by calculating what has to be accomplished. Assume the body is the same size as the moon and is aimed at the center of the earth. It therefore needs to ...
anon's user avatar
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2 votes

The magnetic force between the earth and the sun

The magnetic force between the two is minuscule compared to the gravitational force. We can get an order-of-magnitude estimate by treating both the sun and the Earth as ideal dipoles. The force ...
Michael Seifert's user avatar
2 votes

Gravitational attraction between two bodies

Newton thought of light as particles ("corpuscles") radiating out from the source. Any radiating source naturally follows an inverse square law because the area of the expanding radiation ...
KDP's user avatar
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4 votes

Gravitational attraction between two bodies

Newton arrived at the $\frac{1}{r^2}$ law empirically quite a while before analyzing the planetary motion in the solar system. He did this by comparing the acceleration $a$ experienced by bodies at ...
Thomas Fritsch's user avatar
1 vote

Gravitational attraction between two bodies

From an experimental point of view, imagine that you do measurements of the gravitational forces at various distances. You would quickly see that half the distance does not just double the force, it ...
Steeven's user avatar
  • 51.3k
-1 votes

Questions about speed of gravity

@Prahar asked, "What do you mean by saying that the sun is travelling forward?" That's easy. "Forward" is an arbitrary name for the direction in which the Sun is moving in the ...
Solomon Slow's user avatar
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7 votes

Gravitational attraction between two bodies

As it turns out, only an inverse square law of gravitation leads to Kepler's laws of planetary motion, which were established prior to Newton's time. Newton had worked out the details privately and ...
Albertus Magnus's user avatar

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