Questions tagged [precession]
The precession tag has no usage guidance.
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MRI and precession
A lot of explanations of the quantum mechanics of MRI discuss the precession of a proton in an external magnetic field, for example here:
http://www.physicscentral.com/explore/action/mri.cfm
Doing ...
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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 ...
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Kinematics of a rolling disk on a static disk (variation of the Euler disk)
I'm puzzled by the following problem. Consider a simple tilted disk $\mathcal{D}$ of radius 1 (in any unit) rolling without sliding on top of a static horizontal disk $\mathcal{S}$. The normal $\...
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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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Stuck on Weinberg's quick derivation of Thomas precession
In Weinberg's Gravitation and Cosmology he has a pretty concise derivation of the Thomas precession formula (Eq. 5.1.13). But I don't get the first step...
A particle with intrinsic spin is under the ...
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Start of gyroscopic precession
Let's consider the classical example, the wheel hung by one side of the axle:
¹
When the wheel is not spinning, it will tilt down the free end of the axle first.
When the wheel is spinning, it will ...
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How would I explain why a top wobbles to someone who has never taken a physics course?
I found this this website that explains the precession of a top, but obviously, it is not comprehensible to a younger student. I am not referring to why tops stay up, just why they make circles that ...
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3 Axis Gyroscope with forced Precession and Limits of Motion
I am working a problem concerning a 3 axis gryoscope, the spinning mass is a magnet (dipole). This is part of a optical sensing device. The inner gimbal is for pitch rotation, and the outer gimbal is ...
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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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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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Where did Paul Gerber go wrong in arriving at the same equation as Einstein in explaining the Mercury anomaly?
We know that Einstein admitted that Paul Gerber's 1898 formula explaining the anomaly of Mercury's perihelion was the same as his own. Reportedly Gerber had made a mistake somewhere, so - even though ...
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How to calculate precision of Pound-Drever-Hall technique?
When I read the fifth section (Noise and fundamental limits: how well can you do?) of Eric's article, I have question.
In this section(page 85 and 86), Eric discussed the shot noise, and gave the ...
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Angular velocity in Euler's equations (Rigid body)
I was confused at something...
Look at these equations:
https://en.wikipedia.org/wiki/Euler%27s_equations_(rigid_body_dynamics)
From what I understood the way we get them is by going into rotating ...
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Can there be precession without angular momentum?
In a wikipedia article it is said:
The magnetic moment has a close connection with angular momentum
called the gyromagnetic effect. This effect is expressed on a
macroscopic scale in the ...
user104372
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Lense-Thirring Precession of short GRBs
Stone et al. 2014 have proposed that the jet resulting from the merger of a black hole (BH) and neutron star (NS) may precess due to Lense Thirring torques
A large rotating mass e.g. the Earth, can ...
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Differential precession due to gravitational waves
To motivate the question, Andy Strominger recently put out a paper on calculating the Sagnac shift of counterrotating beams due to the angular momentum flux of a passing gravitational wave.
See here:...
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Precession period matching solar year
Consider the case of a tidally locked planet: its axis of rotation must be perpendicular to the plane of its revolution around the parent star. Therefore, no precession.
It is possible for a planets ...
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Does Celestia take the lunar orbit precession into account?
Does the lunar orbit plane rotate (8 year period precession)? Does Celestia take this into account while drawing the moon orbit?
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Is Energy conserved in a spinning top?
When we spin a top (give it kinetic energy $K_0$) and place it on a table, it starts precessing around the vertical axis.
Is the total energy of the spinning and precessing top equal to the initial ...
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Why $\vec{\mathfrak{m}}$ and $\vec{J}$ are collinear when considering precession in magnetic field?
Recently I have read about magentization of paramagnetic materials and precession of atoms in magnetic field. So, I found the following formula: $\vec{\mathfrak{m}} = \Gamma \vec{J}$, where $\vec{\...
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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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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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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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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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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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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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Quick question regarding Larmor precession and bar magnets
So I was just reading a bit about magnetic dipole moments, Larmor precession, angular momentum etc., but there was one little thing that was bothering me. As far as I know, any angular momentum will ...
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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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Does the angular velocity of a wheel affect its height in this situation?
If there were no friction at all, and the wheel was spinning with some angular velocity in the initial picture shown below. Would the wheel stay perpendicular to the ground regardless of the angular ...
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How can magnetic dipole align if there is precession?
In my lecture notes on paramagnetism and diamagnetism is stated that "according to van vleck critical considering an electron in motion around the nucleus diamagnetic and paramagnetic effect ...
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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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Can we measure the angular momentum of a magnetic domain using precession?
The amount of angular momentum of a single iron atom is small, just $\hbar / 2$. In a single magnetic domain, though, all of the iron atoms have their spins aligned. Presumably, it should be possible ...
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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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Planar Precession Frequency of Orbit
What is the general relation between orbital precession $\Phi$, orbital frequency $\Omega$ and a radial perturbation frequency $\omega$?
For certain cases the answer is "clear", for example:
1) If $\...
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Does Earth's precession rate change with the seasons?
As Earth's precession is caused by the differential solar, etc., attraction to its 'spare tire', then does the rate go to ~zero at the equinoxes and ~twice the average at the solstices? (preferred ...
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How is the precession rate of planets calculated? For which planets do we know the precession rates?
From what I've read, precession rates of Earth, Mars and Moon are known. Why is that?
And how is it calculated?
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Motor-powered gyroscope's precession speed
I was doing experiment about the gyroscope's precession speed and I made my own gyroscope, which is the one in the picture. It is the motor-powered gyroscope as I found out the one made with bearing ...
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Precession of Mercury (Python simulation)
I was trying to simulate the precession of Mercury based on the perturbed solution, and my questions about its implementation in python can be seen here: https://scicomp.stackexchange.com/questions/...
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Larmor Precession of a macroscopic number of electrons
I know that there are some similiar questions out there, but I'm still quite puzzled by the following problem. Say i have a box full of interacting electrons ( I'm not sure if it would change anything ...
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Direction change of gyroscopic precession with change in moment of inertia
In the classic bicycle wheel gyroscopic precession, using the right hand coordinate system of xyz and right hand rule of rotation,
Such as
X axis is in the longitudinal direction (spin axis)
z axis ...
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Why do nuclei precess in magnetic fields?
I understand that a classical bar magnet will precess about the axis of an external magnetic field. Whilst researching NMR, I have read that nuclei with half-integer spin which are subject to an ...
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How to obtain Mercury Precession equation $\frac{d^2u}{d\theta^2}+u=a$?
Let $r=R(t)$ and $\theta=\Theta(t)$ describe the orbit of the planet. Define $$u(\theta)\equiv\frac{\bar r}{R[\Theta^{-1}(\theta)]}$$ where $\bar r=5.83\times 10^{12}$ cm be the mean value of the ...
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Response of a loop of current vs. a rigidly rotating charged ring to a magnetic field
In a uniform magnetic field, a loop of current on a wire will feel a torque that makes the magnetic moment of the loop align with the field direction. But for a rigidly rotating ring of charge, its ...
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How can precession produce a torque in the direction of precession when it has no angular momentum?
I this video, an 8 lb gyro on a rod supported at one end is spun up to several thousand rpm, and an assist is use to get the axis nearly horizontal. A small stick is used to nearly instantly stop the ...
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Proton spin precession and alignment to magnetic field in NMR
Precession due to magnetic field occurs when the magnetic moment of a small coil is proportional to its angular momentum ($\vec{m}=g\vec{L}$). This is due to Euler momentum equation, which for such a ...
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Is it possible to change the speed at which a wheel is freely spinning by moving only its axle?
Suppose we have a wheel spinning on a perfectly lubricated axle. Is it possible to change its angular velocity about that axle, by moving only the axle?
Due to the wheel's symmetry about the axle's ...
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Non-swinging Foucault's pendulum
If there is a stationary pendulum, say at the North pole, neglecting torsion, etc. will it seem like spinning around its axis from the reference frame fixed to the Earth's surface. If so, will it ...
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Equation to tell if precession will happen?
So I have an seen the equation to calculate precession but it breaks down at when there is not sufficient angular momentum, for example if an object is not spinning we divide by zero and the ...
