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Questions tagged [orbital-motion]

The path a body takes while moving through space under the influence of the gravitational forces of other bodies

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Two different ways of finding the speed of a low-earth circular orbit [closed]

I would guess that in a secondary-school physics course, if you're asked to find the speed of a low-earth circular orbit, you might be expected to use the $v^2/r$ formula. But here's another way: Via ...
Michael Hardy's user avatar
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Better equations for modeling and simulating a halo orbit?

I'm trying to model a halo orbit at low altitude (10m from surface). The satellite is using propulsion to trace the circular halo path. It looks like this "from the top" (the blue ball is ...
Nico Brenner's user avatar
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Restricted 3-body: one large mass and two smaller ones

A restricted 3-body problem is usually understood as two large bodies and one much smaller one that doesn't affect the motion of the other two. I am curious about a 3-body problem with one large body, ...
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Dynamics problem [closed]

A 150-kg space vehicle passes through the origin of a newtonian reference frame Oxyz at time t = 0s with velocity o = (100 m/s)i relative to the frame. Following the detonation of explosive charges, ...
Zana Kadher's user avatar
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7 answers
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What changes the velocity perpendicular to radius in an elliptical orbit?

I'm working currently on a problem that asks to justify that angular momentum and kinetic energy conserves for a planet in an elliptical orbit. Although I've been taught that angular momentum should ...
RChen's user avatar
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Find eccentricity of orbit given the velocity and the semi-major axis

Is it possible to calculate eccentricity of orbit knowing only the semi-major axis and the velocity of both celestial bodies? If not, what other additional information is required. Does the fact that ...
Sid N's user avatar
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The magnetic force between the earth and the sun

There is a magnetic field around the earth and a stronger one around the sun. I guess there should be a magnetic force between the sun and earth. Now, shouldn't we take the magnetic force into account ...
Future Math's user avatar
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4 answers
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Gravitational attraction between two bodies

While the gravitational force between two bodies is directly proportional to their masses, and inversely proportional to the distance between them is understandable / seems logical, how did Newton ...
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Questions about speed of gravity [duplicate]

If gravity "travels" at $c$, and the sun is travelling "forward", does it mean the planets are actually orbiting various points "behind" the center of the sun? Does it ...
Curious Steve's user avatar
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When are two object guaranteed to keep getting further and further away?

In a two-body problem, it is known (if I understand correctly) that if the specific orbital energy of the system is $\varepsilon \geq0$, then the objects must eventually escape each other. My question ...
Remeraze's user avatar
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Deflecting a lunar mass with consecutive nuclear explosions [closed]

I'm looking for help in determining the amount of deflection an object with a mass of roughly $7\times10^{22} \,\text{kg}$ (a lunar mass) needs from colliding with a planet. Let's stipulate that the ...
Victor Bergman's user avatar
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Would an Hypothetical Ringworld Positioned Inside the Moon's Orbit Around Earth, gravitationally affect Earth?

If a ringworld were to encircle Earth within the orbit of the Moon, would it induce any gravitational alterations on Earth? I grasp that inside a circular structure, there might not emerge a ...
wepajakeg's user avatar
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1 answer
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Which of Kepler's laws would remain true if the force of gravity were proportional to the product of squares of each masses?

I was asked this question recently on which of the Kepler's Three law would remain if we changed the force of gravitation to be proportional to the product of squares of each masses instead of just ...
Shivansh Jain's user avatar
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Initial positions and velocities for the three-body problem

I have made a simulation of the three-body problem, it follows the euler's method of solving differential equations. I have tried some initial positions and velocities of the bodies and have observed ...
Ronny's user avatar
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Despite tides the Moon, as far as I know, doesn't slow down. Where does the energy come from? [duplicate]

Hy, I don't have anything to do with physics, so please forgive me if I explain my question in a weird way ;) As the Moon rotates around the earth it is creating tides and waves on the earth. IE it's ...
Jakob S.'s user avatar
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Speed of satellite in elliptical orbit [closed]

A satellite $S$ orbits a planet of mass $M$ in an elliptical orbit. At perihelion, $S$ has a tangential velocity of $v_1$ and is distance $r_1$ from the planet. At aphelion, $S$ has a velocity of $v_2$...
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With what vel. would you have to launch an object vertically up from the earth's surface for it to land back again at it's initial launching point?

[Can skip reading this part] First of all, Newtonian gravity shall be considered whilst trying to solve this question. It's been on my mind for a long, long time and has been bothering me since. I ...
Kyathallous's user avatar
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2 answers
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How do two things attracted to each other move in mechanics?

Okay very simply: If you have two objects in 1D and they're both attracted to each other by some force (say there's a spring pulling them both towards each other, or Coulomb's Law or something)... How ...
Shelby Longbottom's user avatar
1 vote
2 answers
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Setting $u$ = escape velocity when calculating the maximum height of a thrown object

So, if I throw an object at some velocity $v$ at an angle θ, the maximum height reached by the object is $\frac{v^2\sin^2{\theta}}{2g}$ but, I know this isnt true. clearly in a weird way, the height ...
uggupuggu's user avatar
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2 votes
3 answers
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Constant speed (at terminal velocity) and zero $g$

I have read the question What would a person experience in a free-falling elevator in a shaft long enough to reach terminal velocity? here and the answer was that you feel exactly the same if the ...
sirzento's user avatar
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Space-for-time Derivative Substitution in Solving for Elliptical Orbit

I am currently working on a simulation of the Newton's Cannonball thought experiment, in which a stone is launched horizontally from atop a tall mountain at a high speed (in the absence of air) and ...
Oscar Jaroker's user avatar
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Elevation angle of LEO satellite as a function of time

Let a point on Earth be denoted with (lon,lat,altitude). Let a LEO satellite be defined by its altitude and inclination. I would like to compute the angular speed and elevation as a function of time. ...
baptiste's user avatar
2 votes
3 answers
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Orbit description in Schwarzschild metric

Suppose to have a restricted 2-body system (BH + star with $M_{BH}\gg M_{\mathrm{star}}$) and you want to describe the orbit of the star relative to the BH, i.e. in the Schwarzschild metric. Usually, ...
gravitone123's user avatar
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1 answer
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How to relate a gravitational plane wave to the GW from a binary system?

I have two different forms of gravitational waves that I am trying to reconcile. A monochromatic GW with angular frequency $\Omega$ propagating in the $\textbf{n}$-direction can be expressed as $$ ...
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How to find the length of a travel between planets using the Hohmann Transfer?

I am trying to figure out how long it would take to get from one planet to another. This is for a worldbuilding project of mine. I would put my question on the Worldbuilding Stack Exchange but I ...
Martamo's user avatar
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Average Speed in one half of an elliptical orbit

I was wondering whether the average speed along one half of an elliptical orbit (say in a star planet system) had a closed form exact solution using Kepler's laws. My approach was using the ...
Echelon96's user avatar
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When is an object no longer considered orbiting a celestial body during its descent?

During the Apollo mission, once the LM began its descent to the surface of the moon, was it still in orbit about the moon?
Bob516's user avatar
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Where can I find spectra data and light curves of a stereoscopic binary star system?

I am trying to find a suitable source of spectra data and/or a light curve of a binary star (no exact star in particular), with which I would use to find velocity and period, and then find masses etc.....
Zandini3's user avatar
3 votes
1 answer
179 views

Speed at which the Moon moves past a point on Earth's surface?

I'm trying to calculate how fast a point on the surface of the Moon is moving past a point on the surface of the Earth (I assume a point on the equator of each for simplicity). I know the Earth is ...
tansvaal's user avatar
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What is the locus of the velocity vectors of a spaceship moving in some distance from a black hole?

Someone with a background in mathematics and limited knowledge of physics asks the following question: Starting from rest, a spaceship is momentarily pushed with a specific amount of kinetic energy in ...
Majid's user avatar
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Impact Parameter as function of orbital parameters

In the case of a binary system (pulsar+companion), the impact parameter $\textbf{b}$ is the projection of the binary separation $\textbf{r}$ on the sky plane: \begin{equation}\tag{1} \textbf{b} = \...
gravitone123's user avatar
1 vote
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Kepler orbit from mass, period, and eccentricity [closed]

I want to calculate the Keplerian orbital elements in the central force case. Given the mass M of the "sun" in kg, the eccentricity $e$ of the orbit, and the period $T$ in seconds, I believe ...
spraff's user avatar
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Applying 1 gram-force for 1000 seconds to 1kg mass

I am looking into ion thrusters and the small amount of propulsion they provide. I am really new to this, so I want to understand. If we have mass of 1 kg in space and we are able to apply to it a 1 ...
The Physics Noob's user avatar
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Approximation of Nearly Circular Orbit by a Precessing Ellipse

I am self-studying the 3rd edition of Goldstein's Classical Mechanics and have hit a roadblock when working a problem (Chapter 3, Problem 20). The problem asks us to consider a planet of mass $m$ ...
kandb's user avatar
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2 answers
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Orbiting body around a star

Let us assume there's a body with mass $m$ and velocity $v$, at a distance $r$ from another body of mass $M$. The velocity vector is perpendicular to the radial vector. With these values, how do we ...
Star Gazer's user avatar
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What is the name of this pendulum? [closed]

What is the name of a pendulum with two parallel string hung vertical to a rod, and giving the rod an initial force would make it swing left and right, doing simple harmonic motion? What is the ...
user398341's user avatar
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Parabolic(?) projectile orbits as an approximation to elliptical orbits given a rotating Earth

Why is projectile motion a parabola given that the Earth rotates and a parabola is an approximation to an orbit. My current thought is that projectiles don't travel in a parabola because if the Earth ...
Steven Dorsher's user avatar
1 vote
1 answer
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Two bodies orbiting around barycenter

There are two bodies with masses $m_1$ and $m_2$ orbiting around barycenter. Distances to both bodies from barycenter are $r_1$ and $r_2$ . First body has known velocity $v_1$ as on the picture : My ...
michal12457's user avatar
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2 answers
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General formula for the frequency

The orbital period of a satellite is the time it takes to complete an entire orbit around the celestial body around which it orbits. I know that the orbital period using the following formula: $$T = \...
Sebastiano's user avatar
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How close does a dwarf star have to be to remove the corona from its neighbour in an elliptic binary system?

It is possible for a larger (wider, but less massive) star to mutually orbit a heavy dwarf companion star in a binary system. If the dwarf star gets close enough it can attract the corona of the ...
spraff's user avatar
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How does moving the pericenter affect the apocenter?

A perfectly circular orbit of a constant height (distance from the center of mass of the orbited planet) around a perfectly spherical planet with smooth surface and no gravitational anomalies will ...
Parzh from Ukraine's user avatar
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Finding the Cartesian position of the lunar ascending node

What I'm trying to derive The Cartesian position of the lunar ascending node relative to the true equator and equinox of date reference frame. My issue is I'm getting a bit tripped up with reference ...
Hunter's user avatar
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How stable are orbits of light objects around twin large bodies?

I know the two-body problem has a stable solution and the three-body problem does not. In the case that there are two comparable large bodies (twin planets) in a stable mutual orbit, what happens to a ...
spraff's user avatar
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3 votes
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Is it possible, by monitoring the brightness of stars, to find a “copy of the Earth + Moon” near them?

More than a dozen Earth-like planets have been discovered around nearby stars based on observations of changes in the brightness of their sun as they pass across its disk (transit events). If an Earth-...
Ванек Огонек's user avatar
1 vote
1 answer
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Is there a way to use the distances of the two opposite apsides to determine the eccentricity of an orbit?

Is there a way to use the distances of the two opposite apsides to determine the eccentricity of an orbit? The ratio between the distances (i.e. perihelion & aphelion) seem like they'd have a ...
madscribbles's user avatar
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0 answers
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Time taken for an object to fall [duplicate]

Time taken for an object to fall is generally given by $$t=\sqrt{\frac{2h}{g}}.$$ But this is only true under the assumption that gravitational acceleration is constant. With variable gravity what ...
Star Gazer's user avatar
1 vote
3 answers
89 views

Escape Velocity from Moon to escape Earth-Moon System

So the escape velocity at Earth is roughly 11.2 km/s, but with the escape velocity of the moon it says that it is 2.38 km/s but since the moon is orbiting the Earth, wouldn't the effective escape ...
Roghan Arun's user avatar
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Don't Geodesics change due to other geodesics?

So the geodesics that point towards the Earth brings space-time towards the Earth and then back out again, but then the moon has its own geodesics so wouldn't it be kind of like geodesics affecting ...
Roghan Arun's user avatar
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Anomalistic periods of Earth and Mercury

Can any one give me a TRUE VALUE for the anomalistic periods of Earth and Mercury? I note the previous question on the following. I more or less implemented the method suggested above using elliptic ...
pwm's user avatar
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4 votes
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Confusion about Post-Newtonian orbital motion (Damour-Deruelle)

In their famous paper in 1985 (link), Damour&Deruelle describe the orbital motion for a binary system taking into account first-order post-Newtonian corrections (1PN). The solution is given in ...
gravitone123's user avatar

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