Questions tagged [precession]

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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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25 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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2answers
51 views

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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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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2answers
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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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1answer
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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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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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1answer
77 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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36 views

Do stellar black hole precess like Earth do?

The precession of Earth caused by the Sun and Moon pull like when you breathe super hard on a spinning top, what about massive blackhole which is a point in space conserving it's angular momentum? I ...
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1answer
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Why don't the electrons in a paramagnetic material precess around an external field?

When a paramagnetic material is placed in a strong external magnetic field, then you'll find that the magnetic momenta of the electrons in the material will align to the field, causing a net magnetic ...
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Why does the Larmor precession frequency depend on $\vec{B}$ instead of $\vec{H}$?

From what I know: The magnetic field strength, $\vec{H}$, is the field generated by a free current flowing on an electric conductor. The magnetic flux density, $\vec{B}$, is a response of the medium ...
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Angular velocity, Angular Momentum and Torque considered vectors to explain gyroscope precession and related phenomena? [closed]

Are angular velocity, angular momentum and torque "real" vectors in the sense that acceleration and force are? Or are they only considered vectors to explain phenomena like gyroscope ...
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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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Will a rotating rigid disk precess in microgravity?

Given a wheel like a disk with some angular velocity $\omega$, will it precess in microgravity?
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Derivation of gyroscopic precession equation: Why is $d\theta = \frac{dL}{L\sin\theta}$?

My textbook gives the following derivation of the angular momentum of gyroscopic precession: The magnitude of the torque is $$\tau = r M g\sin\theta.$$ Thus $$dL = r M g\sin\theta\, dt.$$ The ...
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1answer
54 views

Gyroscopic forces due to counter rotating electric motors [closed]

I am currently working on a tilt rotor aircraft, for that I need to size a motor the applies the torque to swivel the propellers from a down facing position into a rear facing position. We are using ...
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40 views

Can you explain gyroscopic precession using only Newton's three linear laws without applying their angular cousins?

Is there an intuitive approach to understand gyroscopic motion based on Newton's laws without passing through angular momentum conservation?
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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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2answers
61 views

What does it mean to multiply the precession of the earth's axis with $\sin{(23.5)}$?

In an online book Geodätische Astronomie: Grundlagen und Konzepte by Albert Schödlbauer I saw a picture of precession and nutation of Earth's axis. In German but I suppose it is understandable. ...
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1answer
62 views

The Precession of the Perihelion of Mercury 43'' / century or 12000 km / century difference to Newton's Laws

I was reading Foundations of Astronomy by M Seeds and was wondering about the precession of Mercury. There he says it is 43''/century or about 29 km per revolution past the position predicted by ...
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1answer
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Lagrangian of a precessing wheel: gyroscope in Lagrangian mechanics?

Let's consider this classical example: I would write the Lagrangian as the one of the spherical pendulum plus the rotational energy of the wheel, but I fail to see how the precession motion would ...
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59 views

Precession of perihelion of mercury - what is the physical difference between the EFE and Newton's law of gravitation

I've read previous posts on this topic but I am still unclear. I am not able to access the mathematics of GR but I would like to know what is it about the solution to the Einstein field equation that ...
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Dual gyro system: will it resist a turning force?

Let's say there are 2 gyroscopes. Both are connected to the same frame (orange). Both are spinning at the same speed, but in opposite directions (red). If I spin the frame (green arrow), the gyros ...
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1answer
82 views

Why does the axis of spinning tops rotate about a vertical axis?

I have noticed that when we make a top spin, the top itself rotates about it's own axis and at the same time its axis of rotation will be moving in circles. How to explain this? Why can't it simply ...
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1answer
59 views

Rotational Work-Energy Theorem and uniform precession of a gyroscope

For a gyroscope in uniform precession, what would happen if we suddenly turn off gravity? Will it stop precessing because there is no torque and so there is nothing causing the direction of the ...
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Rolling wheel precession

I wanted to write the equations of the motion of a tilted spinning wheel. I am aware of the effects of precession on spinning things, and I know the equations for the case where the pivot point of the ...
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2answers
173 views

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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Which way does a symmetric top precess and why?

I'm calculating the (instantaneous) rate of precession of a symmetric top (i.e. $I_1=I_2\neq I_3$) that is tilted at angle $\theta$ to the vertical if a torque $\vec{G}$ is applied, as shown below: ...
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Do electron have a rotational North/South and magnetic N/S?

Out of curiosity I wonder can an electron have a rotational North/true South which is different from it's magnetic North and magnetic South, if so can we measure the precession?
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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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1answer
68 views

Solar frame dragging

Does solar frame dragging induce a higher centrifugal force to Mercury so its orbit is precessing as well as being more outwards than it should be if there wasn't solar frame dragging?
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163 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
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Why can a gyroscope go upright for a while, after losing some energy?

There are many questions about gyroscopes, and this one: (Confusion about what happens when the rotating axis of a gyroscope is rotated) remind me of an odd behaviour of a toy gyroscope that I had. ...
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About Mercury perihelion again

Sorry to bother you, but I did not get anywhere answer what exactly moves Mercury periapsis. "Sun gravity" or "GR" or "warp of spacetime" are very broad answers, I want to know how they affect this ...
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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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Manev potencial and some problems with it [closed]

Given the Manev potential by the equation below $$\ V_M(r) = - \frac{-mMG}{r} \left(1 + \frac{\gamma MG}{c^2r}\right) $$ in which: M is the Sun's mass; m is the planet's mass; G is Newton's ...