Physics Stack Exchange
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Questions tagged [precession]

282 questions
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6 answers

What did general relativity clarify about Mercury?

I frequently hear that Kepler, using his equations of orbital motion, could predict the orbits of all the planets to a high degree of accuracy -- except Mercury. I've heard that mercury's motion couldn't be properly predicted until general…
Carson Myers
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How do you calculate the anomalous precession of Mercury?

One of the three classic tests of general relativity is the calculation of the precession of the perihelion of Mercury's orbit. This precession rate had been precisely measured using data collected since the 1600's, and it was later found that…
David Z
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7 answers

Why don't spinning tops fall over?

One topic which was covered in university, but which I never understood, is how a spinning top "magically" resists the force of gravity. The conservation of energy explanations make sense, but I don't believe that they provide as much insight as a…
Casebash
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5 answers

Why does a spinning top get back upright when knocked?

I have observed that, a spinning top, when toppled by knocking it with finger, becomes almost upright again (with negligible precessional motion), instead of undergoing precession while being heavily leaned. I cannot find which force produces the…
Archisman Panigrahi
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13
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4 answers

What is the physics of a spinning coin?

When we spin a coin on a table, we observe 2 things: It slows down and stops after sometime. It does not stay at just one point on the table but its point of contact with table changes with time. I was trying to explain quantitatively this but I…
Sahil Chadha
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13
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1 answer

Feynman's wobbling plate

Let us consider a symmetric top, i.e., a body whose mass distribution has axial symmetry (a cylinder, a disk, a cone, etc) free of any external torque. The Euler equations for this body…
Diracology
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13
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1 answer

Details of Newtonian Prediction for Mercury's Precession

Could anyone point me to a book or outline the methods used to actually calculate the 532 arcseconds per century that Newtonian theory apparently predicts for Mercury's precession. I am completely comfortable with getting GR's 43 but don't even know…
Tomas Smith
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What's wrong with this application of Thomas Precession to circular motion velocity measurements?

If you happen to have the Third Edition of Classical Electrodynamics by John David Jackson, turn to section 11.8, as that's where I'm getting all this from. If not, you should still be able to follow along. In said section, Jackson gives us this…
Izzhov
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What happens to orbits at small radii in general relativity?

I know that (most) elliptic orbits precess due to the math of general relativity, like this: source: http://en.wikipedia.org/wiki/Two-body_problem_in_general_relativity I also know that something is different for orbits at radii below a certain…
Alan Rominger
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10
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2 answers

Intuitive explanation of why orbits are closed?

Yesterday my brother asked me how orbits work. Suppose for the sake of the question that you are trying to put a rocket in orbit around the Earth. I explained that orbiting is essentially being in free fall while going very fast sideways, so that by…
Javier
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Does General Relativity predict Mercury's orbital precession without other planets?

From Newtonian mechanics, the precession of Mercury can be calculated by taking into account the gravitational pull of other planets. From that, I assume that in the absence of external planets, Newtonian mechanics predicts that the elliptical orbit…
Stallmp
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Weird rotational motion of a heavy thick disc

I and my friend noticed a strange behaviour of a rotating disc (or a cylinder) and we don't know how is that happening. This is the video. Actually what is happening in the video is that the disc wobbles (the rotational axis precesses about the…
Ankit
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Mercury's Orbital Precession in Special Relativity

I am researching Mercury's orbital precession. I have considered most perturbations and general relativity. I am still not satisfied. I need your help. I need a solution to Exercise 13, Chapter 6, in Ref. 1 (which is Exercise 26, Chapter 7, in both…
Raghu Singh
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Feynman's disk paradox used as a gyroscope?

I have recently learned about Feynman's disk paradox, where angular momentum is stored in the properties of the electric field. One example would be a coil with current going through whose axis is shared with a disk carrying charges on its edges. As…
uniquehorn
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3 answers

Why objects with magnetic dipole moment sometimes orient towards external B and other times they do precession?

Given the magnetic dipole moment in external uniform magnetic field $\vec{B}$, I am trying to understand why sometimes $\vec{\mu}$ simply aligns with the $\vec{B}$ and stays that way, while other times $\vec{\mu}$ starts precessing around…
matori82
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