Questions tagged [precession]

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Relation between Zeeman effect and Larmor precession

I'm wondering if there's some intrinsic reason that the precessional frequency, $\omega$, of a spin about an external magnetic field matches the frequency of a photon emitted (or absorbed) in ...
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1answer
293 views

Larmor Frequency for Spin Transition

http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/larmor.html Consider the process of Larmor precession of the magnetic moment associated with the spin angular momentum of an electron inside a ...
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702 views

Anti-gravity wheel?

So I was just watching some YouTube videos on a spinning wheel that seemed to "defy" gravity. The creator made two videos on it, the first showing the wheel, and the second with an attempt ...
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2answers
618 views

How does precession affect angular momentum?

I have been studying Irodov's problem book. There are a lot of good problems that challenge conceptual knowledge, and so I have to ask somebody for a qualitative answer. I can best describe my ...
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1answer
190 views

How much force is required to break precession?

Gravity, in this diagram, provides a downward force creating a torque that causes the wheel to precess around the chain. This is cool but counter intuitive, and I am wondering what force is needed to ...
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14 views

How much differs the Mercury speed at perihel from its theoretical speed with no frame dragging involved?

How much differs the Mercury speed at perihel from its theoretical speed with no frame dragging involved? Can a formula of frame dragging velocity be calculated regarding the distance of a point of ...
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2answers
226 views

Gyroscope precession and Euler equations

I've been trying for so long to solve this problem, but the solution I have found isn't the one I expected. Basically, I have to solve Euler's equations for a gyroscope with a weigth at a distance d. ...
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1answer
198 views

Does asymmetric rigid body experience torque-free precession?

I know that a top (or any axis symmetric body) experience torque-free precession. and I know that asymmetric body, with 3 different dimensions has stable rotation when the angular velocity is near the ...
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1answer
39 views

What are centripetal forces for flywheel precession movement?

What are centripetal forces for this flywheel? I suppose for rotation around "inner" axis centripetal force is due to attractive forces between particles inside flywheel. However what about ...
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1answer
24 views

Does precession affect loss of angular velocity in collisions?

I'm a higher schooler trying to do a project on how moment of inertia affects loss of angular velocity in spinning top collisions. Right now, I'm trying to find factors that might affect my results ...
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1answer
41 views

What is the Precession direction of positron?

In Larmor precession; The spin angular momentum of an electron precesses counter-clockwise about the direction of the magnetic field(An electron has a negative charge, so the direction of its magnetic ...
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2answers
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Feynman Lectures: 20–3 The gyroscope

In the The Feynman Lectures on Physics, Volume I, Chapter 20, Section 3,The Gyroscope found here, Feynman wrote We note that when the wheel is precessing, the particles that are going around the ...
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275 views

Understanding work with rotational momentum/moment of inertia

Apologies for the basic question but between the vectors and the spinning, I'm getting confused. If I have a wheel with moment of inertia $I$ spinning at some rate $\vec\omega$ around an axis, what ...
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2answers
158 views

Would a black hole's rotational axis precess in orbit around the sun?

The earth rotates, and its axis of rotation precesses due to the gravitational pull of the sun and moon and other planets upon the mass of the earth. If an earth-sized, rotating black hole was in ...
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50 views

Intuitive derivation for the precession rate of a spinning wheel

The derivation of the precession rate of a wheel hanging from a rope, as shown below usually involves taking the total torque acting on the system and equating it to the change in angular momentum. ...
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1answer
205 views

Precession of Angular momentum of Symmetric Top

For a torque free symmetric top, is the angular momentum in body fixed coordinates in same direction as instantaneous axis of rotation? I know that instantaneous axis of rotation precesses about ...
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1answer
38 views

Derivation of precession rate of a wheel gyroscope [closed]

I searched on the web and all I could find is the precession rate of a spinning top. But what I want is the derivation of the precession rate of a wheel hanging from a rope, as shown below: which is ...
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4answers
14k views

Direction of torque precession of a spinning wheel

Consider a spinning wheel, which is held up by one end of it's axis like this: To explain why the change of angular momentum is directed as shown in the figure above, one usually says that there is ...
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2answers
579 views

Gyroscope precession

I have a system diagrammed and explained in the image below. Experimentally I believe the wheel will rotate around the pivot point where the cable is attached in a counter-clock motion if observed ...
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2answers
67 views

Combining Newtonian Gravity and length contraction from SRT?

The value of $\gamma$ that I will use is $$\gamma=\sqrt{1-\frac{v^2}{c^2}}$$ And length contraction is $$L_0=\frac{L}{\gamma}$$ Where all variables have usual meaning. Let the gravitational pull on ...
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3answers
113 views

How do I calculate Earth's axial precession in an idealized Sun-Earth system?

I am experimenting with an idealized two-body system based on the Sun-Earth system. I want to calculate how much Earth's axis precesses and nutates given the simplified setup. In my system, the orbit ...
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1answer
343 views

Nutation frequency for a weighted gyroscope

So, I've been led to believe that the frequency of nutation of a gyroscope can be calculated using the formula In which the I's are the moments of inertia around the principal axes and omega-3 is the ...
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3answers
131 views

Confusion on conservation of angular momentum

Can someone explain how angular momentum is conserved while at the same time precession in freely rotating objects happens? It seems contradictory.
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16 views

Do paired electrons precess under a magnetic field? Is there a way to know?

The spins of paired electrons are opposite of one another, but so are their magnetic moments. Thus, an externally applied magnetic field will exert opposite torques to opposite spins. Doesn't that ...
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3answers
94 views

Gyroscope precession: angular momentum and torque

I recently bought a Gyroscope toy online and was keen to find out the Physics behind this fun little "gravity-defying" toy. I did some online research and found a force diagram of a ...
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1answer
42 views

Why does the gyroscope oscillate a little when it just starts to precess?

I was reading up on why before starting the precession the gyroscope "goes down a little", (Link at the bottom). In this paper, while looking at the graphs I observed that before reaching ...
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3answers
153 views

Is it possible to estimate the 23.5° tilt of Earth's axis?

Using the value of the precession of Earth's axis in 25,800 years and the value of Earth's radius, mass, moment of inertia etc., would it be possible to calculate/estimate that Earth's axis must be ...
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48 views

State of the art on relativistic perihelia precession in Solar System (other than Mercury)

The correct prediction of anomalous precession rate of Mercury perihelion is a classical test of General Relativity and one of its' big triumphs. How about other planets in the Solar System? ...
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1answer
41 views

Is precession a property of asymetric objects only? How to explain Larmor precession?

Is precession a property of asymmetric objects only? How to explain Larmor precession? A proton could be asymmetric due to its compositeness but what about electrons?
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15 views

What is the relative importance of the Coriolis term to the precession term in frame dragging by rotating Kerr black holes?

The Wikipedia entry for Thirring precession describes the Coriolis term as separate from the precession term. Is it fair to say that when looking at the dynamics of a rotating black hole, the ...
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1answer
65 views

Does Newton's Theory with Retarded potentials give rise to the motion of perihelion of Planets

If we take into account the retarded potentials and the motion of the Sun(due to the planet), does Newton's Gravitational theory give rise to the motion of Perihelion of planets (qualitatively, not ...
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8answers
17k views

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 ...
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21 views

is room temperature quantum (qubit) nuclear magnetic resonance possible?

I know it is possible to do room temperature NMR. Not just that but one can also use the earth's magnetic field for the nuclei to precess about. If done this way, one gets precession at about the KHz ...
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47 views

Precession of a flywheel on earth

I’m currently working on a mechanical problem and I’ve got a couple of questions. First, let me describe the problem. We’ve got a flywheel somewhere on the surface of the earth spinning merrily. It is ...
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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 ...
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30 views

Gyroscopic Torque

I was going through this problem in which there was a disc mounted at one end of the rod and the other end of the rod is hanged using a rope. The disc is given angular velocity counter-clockwise. Now ...
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1answer
78 views

The acceleration of gyroscopic precession

If we take the movement of a rotating gyroscope held horizontally at one end with a rope, then the rotational momentum of the gyroscope's spin exists, as well as the rotational momentum caused by ...
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1answer
23 views

Difference in the precession regarding the gravitational gradient

Let say a less massive star acts on a planet causing it to precess.Does a more massive star cause less precession of this planet if in both cases the gravitational force applied to the planet center ...
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1answer
315 views

How to relate spin speed and time in which a gyroscope falls beyond some angle?

Usually physics books calculate the precession rate of a gyroscope when its momentum wheel is spinning "fast enough." I am looking for an equation to calculate the wheel speed whereat a ...
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1answer
28 views

How do frame dragging affects a photon for outside observer?

I remember an analogy that explained this phenomenon using magnetic field, a charged particle will experience a force next to another spinning charged particle or something like that. But I don't want ...
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74 views

Why stars don't precess?

Assuming that rotation of stars, galaxies etc is determined basically randomly, the question is: why do all space objects rotate so 'neatly', with little or no precession? And what precession there is ...
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19 views

Inertial precession of a rigid body

Is inertial precession of a rigid body possible? In other words, can [axis of rotation of a rigid body] rotate itself inertially and perpetually around the center of mass? Assuming no torque, no ...
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1answer
177 views

Is there still an anomalous precession in Mercury's orbit that GR doesn't predict?

I was reading through the Wiki pages on tests of relativity and I was curious about this section. Am I interpreting it correctly? Is there still about $1.21''/\text{ cy}$ of precession (Total ...
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3answers
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Does the length of the sidereal day vary systematically?

I'm confused about some properties of the sidereal day, in particular whether its duration varies systematically over the course of the year.1 It seems to me that that must be the case, but the ...
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1answer
25 views

Precession - why decompose to angular momentum component?

I always see it is conventional (in Landau-Lifshitz for example) to decompose the angular velocity vector to 2 components: axis of symmetry and angular momentum vector, and then define the angular ...
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2answers
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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 ...
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1answer
66 views

Precessional motion of a spinning top

In Feynman's book, when he talks about the motion of a rapidly spinning top, he mentions: "When we apply a Torque to a rapidly spinning top, the direction of the precessional motion is in the ...
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1answer
113 views

Centripetal force in a gyroscope

I realize there is another question on the centripetal force involved in a gyroscope's motion, but I found the answer to not be very complete. With respect to a gyroscope attached to a vertical spring ...
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1answer
39 views

Conceptual Question About Gyroscopic Precession of body about Two Axes

I've been trying to glean some insight into the motion of a body that is rotating about an axis through the COM of said body whilst traveling in a orbital-like path about a perpendicular axis outside ...
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64 views

Precession of a closed orbit under a central force other than the inverse square force

Consider the motion of a closed orbit in a central force field ${\bf F}({\bf r})$ other than the inverse square force i.e., $${\bf F}({\bf r})\neq -\frac{k}{r^2}\hat{\bf r}.$$ However, since ${\bf F}({...

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