Precession Definition and 259 Threads

As title. Thank you. In the context of MRI, why/how does applying 90 degree radiofrequency at Lamour frequency put proton precessions into phase? I understand 90 degree RF minimises net magnetic moment, such that there is least difference between number of protons in parallel (with...

Consider a top spinning. From experience we know that it's harder to tip over if it's spinning. I believe that is due to precession but I'm not sure why. I can see when I draw torque and angular momentum vectors, that the angular momentum vector just gets "shifted" a little to the right (or...

Hi, I'm having some trouble understanding how this works. I'm trying to put the pieces together but I'm hoping people here can help me. Specifically I'm wondering about a gyroscope positioned so that its axis lies in the horizontal plane and one end sits on top of a rod. So far what I've got...

Hello everyone, I'm having a really confusing time trying to get my head around these concepts, so I will try to explain what I can... So, in proton NMR we have nuclei that can be in either spin-up or spin-down states. Nuclei align with an external magnetic field but precess. (This precession...

Im trying to understand the physics of the precession of a spinning top. What determines the tilt angle (the angle the top is tilted off the vertical axis)?

I am having trouble understanding something about the precession of Mercury. The precession takes place in the same direction of motion as the orbit of the planet, so that the ellipse of the orbit becomes angled slightly more forward over time, right? In a gravity simulator, this amounts to an...

The Schwarzschild metric allows to calculate the precession of an elliptic orbit of a particle around a large central mass, provided the mass of the particle is much smaller than the central mass M. This condition is not met in the case of binary stars m1 and m2 revolving around each other...

Let’s say that a space probe orbiting the Sun in an elliptical orbit prove would emit heat towards the motion direction., and hence causing resistance against motion. Let’s say it would happen only when it was moving from aphelion towards perihelion, - and that the motion resistance is 1E-9...

The angular speed of precession for a gyroscope is given by ω_{p} = T/ω_{g}. So that the rate of precession increases as the gyroscope, top, or wheel slows down. This agrees with observations of a top, which wobbles around very quickly as it slows down. If I hold a bicycle wheel in my...

In classical mechanics, an asymmetric rotating object will generally precess. Expressed in the body-fixed normal system of the object, we have I_i \dot{\omega_i}=(\vec{L}\times \vec{\omega})_i where L_i=I_i\omega_i. Choosing a simple example where I_1=I_2, we obtain \dot{\omega_3}=0 and, for...

There is so much confusion regarding the anomalous precession of Mercury's orbit. Mercury's orbit precesses at 575 arc-secs a century. Classical mechanics accounts for all except the anomalous 43 arc-secs. General relativity (curved space-time) accounts for the 43 secs. There are other theories...

So I've been working on understanding precession better. I had a whole other thread where it was explained to me how a torque applied to an object with angular momentum can result in precession. But this is sort of a different question, so I'd like to start a new thread for it. In my physics...

Anyone know who was the originator of the matrix in the jpg file?

Does anyone know if anybody had successfully explained mercury’s anomalous precession before GR? The reason I ask is that I recently ran across this paper online. It seems to easy to not have been done after SR but prior to GR. Link: [url]http://toe.sytes.net:65333/planetary%20precession.pdf

Hi guys ! Im trying to get my head round precession, nutation and spin. Suppose I have a cylinder of height L, base radius R. Initially it is just spinning about its central axis (i.e. line joining cone tip to the centre of base). In this scenario, centripetal acceleration experienced by say...

Hello. I have a formula for gravitational acceleration http://www.part.lt/img/eb4c24f748f6e9a2797ed354bfbe6051663.png And I have tested it by numerical integration. It looks it gives perfect results. For example 0.104 arc seconds per revolution for the Mercury precession. But I have no an idea...

Homework Statement Consider an electron with spin, which should be in a homogenous magnetic field B=B0ez. This situation is described by the Hamiltonian of the shape \hat{H}=g\frac{\mu_B}{\hbar}\textbf{BS}. Consider now the time dependent state |\psi(t)> of the electron in spin space. The...

Homework Statement I have two questions. Both involve derivations from textbooks, not end-of-the-chapter problems. The two textbooks are Quantum Mechanics by Griffiths, and A Modern Approach to Quantum Mechanics by John Townsend. My first question is about the discussion of Larmor...

Homework Statement Hi. I have: A 3 kg bicycle wheel rotating at a 2484 rev/min angular velocity has its shaft supported on one side. When viewing from the left (from the positive x-axes), one sees that the wheel is rotating in a clockwise manner. The distance from the center of the wheel to...

The precession of Mercury is presented as one of the threshold moments for general relativity. Are there any publicly available summaries of the classical anomaly? Most refer to a 1947 paper that uses an outdated reference frame. Clemence, G. M. (1947). "The Relativity Effect in Planetary...

Homework Statement The Hubble Space Telescope is stabilized to within an angle of about 2 millionths of a degree by means of a series of gyroscopes that spin at 1.92×10^4 rpm. Although the structure of these gyroscopes is actually quite complex, we can model each of the gyroscopes as a...

i have some troubles to understand the lamor precession properly and i need your help to correct my errors: so in order to get the lamor precession: afaik you need something that causes a magnetic moment, e.g. an electron with spin or angular momentum. then you need a homogenous magnetic field...

I've been reading up on gravity probe B and the results, but I have a question about precession in general - I've heard it said that since the gyroscopes are in free fall there is no classical precession to be expected. So then, what explanation was there for Earth's precession before...

This is a continuation of https://www.physicsforums.com/showthread.php?t=526249", now that my confusion on Thomas precession has been clarified and my root question has been shown to not stem from this effect. In classical mechanics for any inverse square force, \vec{F}=-\frac{C}{r^2}\hat{r}...

I have been reading about Thomas precession and have encountered many papers that appear to give conflicting accounts of its magnitude and direction. In particular I am considering the portion of the DeSitter precession that is accounted for by the Thomas precession. I have found values...

Einstein used General Relativity to explain the aberrant precession of the planet mercury in its orbit around the Sun and was shown to be correct. What the dickens , in 10th grade English, does the "precession of mercury" mean?

I know what each word mean independently, I'm just confused as to what sort of motion is trying to be described as a whole.

I'm brushing up on my knowledge behind the physics of NMR. Turns out there was a lot I had misconceptions about; I thought it was very similar to absorbance/transmittance spectroscopy. I read some material about it which threw that idea out the window. I'm now looking at a video that shows a...

Can someone explain the cause of the Precession of Mercury’s Orbit in a "language" so simple that my grandmother can understand it? I mean only the part (43 arc second) that is due to relativity.

One complete orbit of perihelion precession of Earth takes about 100,000 years How long time take one complete orbit of the perihelion precession Jupiter ?

Hi, It's found it Carroll that r=\frac{L^2}{GM(1+e\cos{((1-\alpha)\phi)}} . He states that this means we've found that during each orbit the perihelion advances by \Delta\phi=2\pi\alpha, I'm not sure that I follow this. Perihelion is the min value of r, and thus should correspond to whenever...

Hi. I am working on a little project involving precession and I'm having a hard time figuring this one out. I am sitting on a chair hold a spinning bycicle wheel in my arms. When I twist the wheel to the side I will start to spin. What governs how fast I will spin? What is the equation...

Hello, I quote http://en.wikipedia.org/wiki/Precession from the first paragraph from the first section ("Torque-free precession"): But isn't the matrix product L = Iωs relative to the moving frame (that's how we did it in our course anyway), meaning L and omega are indeed the vectors as...

I'm interested in the change of orientation of a football as it travels through the air Really quickly, I'm going to define a reference frame as such: x-axis: from one touchdown to the other, and in this case, also the line from quarterback to receiver. y: along the turf from sideline to...

Trying to analyze all the dynamics of gyroscopic type motion. Assume the Z axis is vertical (which the wheel precesses about) Have a spinning bicyle wheel, that is held up via string on one end, the biycle wheel begins to precess about the vertical axes via torque induced from gravity...

Is precession caused by uneven mass distribution in the gyroscope, or by an uneven supporting surface, causing a couple to form (i.e., normal force and gravitation force start to have non-zero cross products)? Is precession analogous to circular motion, the angular momentum vector is having its...

When you have a spinning top undergoing forced precession (due to the torque created by its weight trying to tip it), you seem to get two precession rates. Why? I get this result from using Euler's equations, specifically that the sum of moments tipping the top is (in the case of steady...

The problem is to calculate the precession of Mercury using a naive approach: {{d(\gamma m \vec v)} \over {dt}} = {-GmM \over {r^2}} So apparently a Lagrangian of the form - mc^2 \sqrt {c^2 - \dot r^2 - r^2 \dot \theta ^2 } - {{Gmm} \over r} gives us a Lagrangian that obeys the previous...

Hi all, As the sun is an oblate spheroid and is rotating, should not the axis of rotation be precessing, much like the Earth does? What is the axial tilt angle and what is the precession period in years? Also, what is the amplitude and period of the nutation? Are there are equations for...

This is not a homework question. This is the result of trying to think of a way to remove seasons. Imagine a case where the Earth's axial precession had a period of exactly one year (instead of about 26,000 years) and that such a precession was counter clockwise (matching the direction of the...

Could anyone give me a descriptive picture on WHY geodetic precession occurs? I understand the equations from which it follows, so I can derive it algebraically, but I would like to get an intuitive feeling of why it occurs too. My problem is the following: parallel transport of vectors along...

When applying GR to calculate Mercury's precession, the result is 43 arcseconds which coincides with the part of observed precession unexplained by Newtonian theory . My question is: why the formula from GR gives precisely this unexpained 43 arcseconds and not the total observed precession of...

I am looking for a derivation of Thomas Precession formula in special relativity. can anybody please suggest any online source (or book) for this?

I am trying to understand how a rotating bicycle wheel doesn't fall over when you hold it on one side of the axle . I read a thing and it says , the top of the wheel wants to go to the left and the bottom of the wheel want to go right but when the wheel rotates these forces appose because...

When calculation GR, the component due to other planets is removed. In that calculation outer planets are assumed to be rings of mass and the effect of that mass is seen to have an effect on mercury precession ...

Almost everything is clear to me as far as the reason for the precession of a bicycle wheel suspended by a string from a rigid support is concerned. But I don't understand one thing about it. There are 2 forces acting on the system- one is the downward force of gravity at the center of mass of...

I ran a search for gyroscopes looking for a definitive solution to the "What causes Precession?" and found no good clear answers. I think the Feynman lectures come close to the solution and followed that thought process, all the pieces point to the solution, I had to put my theory to the test on...

Hi, anybody knows of a book/article/source of any kind where I could check an actual rigorous derivation of the Sun's torque acting upon Earth? There's a couple of things I don't fully comprehend, maybe someone here could help me. 1- Why is it that if Earth would be a perfect sphere there...

Hi guys, Is there a Thomas precession for a motion along a geodesic line in a curved spacetime? If yes, consider a little giroscope moving along a circular orbit in the Schwarzschild metric. What is the precession after a full cycle?

In the following question: http://phstudy.technion.ac.il/~wn114101/hw/wn2010_hw12.pdf How Do I caculate the precession rate in 4C? And also in 4D?