Questions tagged [precession]

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71 views

Which way do Feynman's plates precess?

I assume people are familiar with the story of Feynman watching students toss dinner plates in the air in the cafeteria, and how working out the relation between the spin rate and the precession rate ...
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Is electron diamagnetic resonance (invoking Larmor precession) possible?

Diamagnetism is observed in materials where electrons are paired. These paired electrons have opposite magnetic dipole moments. Therefore, the total magnetic torque on the pair's magnetic dipole ...
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Why does a rotating mass generate a torque on an attached object?

In this video, we see a little toy vehicle with two wheels that is unstable by itself. However, when an attached gyroscope is running (a rotating mass) it stabilizes itself. When the mass starts to ...
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Why does a precessing wheel remain horizontal, instead of flipping?

Suppose I have a wheel with an axle, such that one side of the axle is tied to a rope. I'm initially holding wheel in such a way, that the radius vectors of the wheel are perpendicular to a board. I ...
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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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40 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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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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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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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
44 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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70 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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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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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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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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124 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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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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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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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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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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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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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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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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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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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
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
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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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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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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178 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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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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143 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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76 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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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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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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Minimum gyro speed to yield force precession

Does anyone know what the minimum speed of a gyro to make it so a force at 0deg will yield a movement at 90deg? or even better, what the angle is wrt speed? see http://www.copters.com/aero/gyro.html ...
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A general question about precession

Does precession (of a top for example) occur only whenever the angular velocity vector is not parallel to a principal axis? I have yet found any clear definition of precession and when it is defined ...
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Difference between nutation and polar motion

If you add a mass to your spinning globe or just change the mass distribution does it increase nutation or polar motion? And How do I calculate nutation? For this I take earth as an example. from what ...
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Do protons and electrons actually precess?

I know that protons and electrons do not actually spin, although they have the property of spin. I was learning about MRI. I was introduced to the idea that you have the spin of the proton in the ...
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Direction of rotation in Feynman's Wobbling Plate

For cube size 0.1,1,1, Mass=100; Initial angular velocity=ω(0)=[1;0.25;0.5]; we get Moment of inertia tensor=I=[16.67,0,0;0,8.42,0;0,0,8.42]; Angular momentum magnitude=|L|=17.32; If body axes=x’,y’,z’...
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Calculate total angular momentum of precessing and spinning wheel, then use result to prove gyroscopic precession formula

Consider the following scenario: https://youtu.be/8H98BgRzpOM?t=27. How would I calculate the total angular momentum of this system? The spinning wheel is rather easy, and it's $L_{\rm wheel}=I\omega$....
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Is the torque on a gyroscope a conventional virtual force perpendicular to rotation?

So I am having some difficulty understanding gyroscopic precession. I understand that mathematically by convention torque is perpendicular to the force and so is angular momentum but surely that force ...
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Are the precession and nutation of Earth's core directly connected with precession and nutation of Earth's magnetic field if they are present?

If the magnetic field of Earth is generated in the core of the Earth can we deduce core's precession cycle by measuring the precession of Earth's magnetic field (not Earth as a material object) or the ...
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Precession of the Magnetic Moment around B

Equation 1.1.31 in this picture. How did the author reach to this solution from equation of motion? would anyone please explain it to me. I tried to derive it but no luck.
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Does spin precession stop immediately after leaving Stern-Gerlach apparatus and split into the orthogonal direction of precession?

A small concept I'm a tiny bit confused about. Sakurai in the introduction to quantum mech introduces the Stern Gerlach experiment. According to his discussion, an $S_{x}+$ particle that goes into a ...
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Why is precession angular velocity constant?

I am currently studying precession, and have a question regarding the angular velocity of precession. Let's simply use a spinning top in this case. I understand that it is given by the formula $$ \...
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1answer
125 views

Precession of perihelion of Mercury?

I have a few questions about precession of Mercury and GR corrections. Feel free to any that you can: GR is used to correct precession caused by Sun on Mercury by time dilation and length contraction....
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113 views

Rotational mechanics in a gyroscope question

I have a homework question about gyroscope rotation, but I will describe my confusion more specifically as follows: Below is the setup of the problem. I understand the concept that if the rotor is ...
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What physical phenomenon causes racing bike to lift automatically after it fall down?

What physical phenomenon causes racing bike to lift automatically after it fall down? What causes it to travel further distance after it fall down? Please help me. Animation: YouTube link :https://...
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766 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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237 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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