Questions tagged [precession]
The precession tag has no usage guidance.
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Is the Laplace-Runge-Lenz vector applicable for test particle motion around black holes?
In classical mechanics , the Laplace-Runge-Lenz (LRL) vector is a characteristic feature of the Kepler problem. This enables a very simple discussion of the properties of the orbit for the problem. It ...
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Why does the gyroscopic precession of a spin-stabilized bullet cause drift in the same direction as the spin?
I am trying to understand the physics behind the gyroscopic phenomenon called spin drift. Spin drift occurs to bullets that are spin-stabilized over the course of their flight.
Spin drift starts with ...
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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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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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How to calculate the distance of Mercury's perihelion shift in meters? [closed]
Since the shift in mercury's perihelion shift is 2.88E-5 degrees and mercury's altitude above the Sun at its perihelion is 46001200000 meters, can I use the formula for an isosceles triangle to ...
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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 I conceptually interpret spin precession?
In Sakurai section 2.1, he works through an example of spin precession where we come to the conclusion that, when working in the z-basis and applying a magnetic field in the z-direction, the spin ...
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Pencil doesn't act as a spinning top
If one spins a spinning top, it'll stay up for a while before falling down. However, if one spins a pencil, it falls down immediately, just like if you didn't spin it at all. My question is why there ...
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Gyroscopic bicycle wheel - forces on the wheel only
This is a standard problem in university physics, which I studied at university in depth. With higher concepts like angular momentum, it is fairly straightforward to explain the motion.
However, one ...
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Can orbiting point masses precess?
In a recent Science News, it mentioned two orbiting black holes (which later combined) were precessing; i.e. their motion did not remain in a stable plane, but rather the plane itself was changing. ...
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Is the diameter of earth's north pole similar to the south? (Think axis of rotation+ axis of precession)
Earth is an oblate spheroid, not a sphere, since it's rotation around the axis causes it to bulge along the equator.
Is it teally a symetric oblate spheroid though, or also not even that?
To explain: ...
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NMR without static magnetic field
NMR is usually conducted by first aligning nuclei to a strong, constant magnetic field, so that you can apply RF radiation with a magnetic component directly perpendicular to the constant field. ...
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Geodetic Precession of a Gyroscope in Hartle's GR Book
In 14.3, Hartle deduces the geodetic precession angle per orbit of a gyroscope in Schwarzschild geometry. Immediately after eq.(14.18), the book reasons that the angle deduced is physically measured ...
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Is it right assume the greater the precession of a type of particle in the same magnetic field the slower the particle spin?
Is it right that the greater the Larmor frequency of a particle measured for same magnetic field applied the slower a particle spin is? I read these articles http://hyperphysics.phy-astr.gsu.edu/hbase/...
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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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Direction of angular velocity vector VS angular momentum vector
I understand that angular velocity and angular momentum velocities don’t need to be parallel to each other. However, I’m confused what these vectors even represent. So I have 3 questions about this:
...
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Confusion about the Spinning Top
Consider the following symmetric spinning top with a fixed point on the horizontal surface.
I have two questions concerning its motion:
let $\underline{\Omega}$ denote the precession angular ...
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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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Will the inner gimbal continue to rotate if no friction?
The picture shows a gyroscope with a rotating disk.
Adding a force to the outer gimbal from a certain direction causes the inner gimbal (plus the disk with bearings) to rotate as well. When the force ...
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Resisting Precession of a Gyroscope
its known that if a torque is applied to a spinning gyro, the gyro will pitch. There's a lot physics on the pitch speed, but what is the torque to induce this pitching?
ps. I am building a gyro ...
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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 ...
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"Precession" of a free electron
I'd like to gain as deep of an understanding as possible of the following diagram from Introductory Quantum Mechanics, 4th ed., by Richard Liboff:
I'm not looking for help with solving the easy ...
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Definition of rotation moment in a vertical surface during forced precession of a gyroscope
I have the following assumption:
Moment of gyroscope flywheel created by gravity force:
Rotation moment of natural precession due to gravity forces:
Since the flywheel does not drop:
However, when ...
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Puzzle with the precession of the neutron spin?
More perplexing news about the neutron spin in this recent Nature Physics publication: arxiv.org/abs/2103.03333 The authors collaboration (more than 100 authors) report a newly experimentally found ...
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Antigravity force in powered precession gyroscope [closed]
I have an idea that a powered for rotation gyroscope with fixed precession can serve as antigravity engine. I also wonder of someone tried an experiment to prove that it does not work.
The following ...
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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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Is Bertrand's Theorem Consistent with GR?
Bertrand's Theorem - Please observe the gif of orbits with different exponents in the denominator. (I couldn't get the image upload feature to work for this)
Note, the orbit with a 1.9 exponent ...
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What explains the descrepancy between Asaph Hall's equation for Mercury's precession and GR?
In regard to What is the weight equation through general relativity?, the answer is:
$$F=ma=\frac{GMm}{r^2}\frac{1}{\sqrt{1-\frac{2GM}{c^2r}}}.$$
This source provides a different equation:
$$f \approx ...
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Does motorcycle counter-steering work by precessional motion?
When a motorcycle is going over a particular speed ($\approx 20$ m/h or 30 km/h) you learn in motorcycle class the best way to steer is using the so-called "counter steering";
I can't find ...
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Newtonian contribution to perihelion precession of Mercury
We have seen that the orbits of the planets around the sun can be
found, to a good approximation, by only considering a two-body system
(a planet and the sun) interacting through a central force. ...
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Gyroscopes and Conservation of Angular Momentum follow-up
I'd like to follow up on a question I asked two years ago under the same title (Sept. 22, 2019).
I am trying to understand just exactly how angular momentum around the vertical axis is conserved ...
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Does nutation require $n \ge 2r$?
I'll start of with my (mis)understanding:
We have a planet orbiting around another body. The orbiting planet has infinitely many axes passing through it, but we're interested in two, $A_1$ and $A_2$. $...
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Is it the centripetal force due to precession that prevents a spinning wheel from falling? [duplicate]
An object tied to a rope will lift when swung around (like in a merry-go-round), due to the centripetal force.
If a rapidly spinning wheel is hanging from a rope at one side of the axis, it won't fall ...
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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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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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NMR: Why does 180 degree pulse turn around direction of lamor precession?
In descriptions of the spin echo measurement sequence, it says
first a $90°$ pulse turns the magnetization sum vector into the transversal plane where it rotates with the Larmor frequency
spins of ...
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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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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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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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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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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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