Circular motion about a central point or axis

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3
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2answers
29 views

Forces on objects orbiting a black hole?

Firstly, please excuse my elementary knowledge and lack of eloquence when writing about astrophysics. I am a dentist, who occasionally thinks about the how the universe works. I'm both fascinated and ...
0
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1answer
44 views

XYZ Axis Orientation - Why are Math Charts and Euler/Pitch Roll Yaw notations different? [closed]

This is the orientation of XYZ chart that I am familiar with. I am looking at the workings of gyroscopes, in relation to mobile phones. A good visualization is planes/rockets for explaining pitch ...
5
votes
3answers
64 views

What happens inside a body when it rotates?

I'm studying rigid body dynamics lately. I came across the definition of torque, and though I've found a lot of explanations as to why there is an r there (the moment), all of them are mathematical ...
0
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0answers
30 views

What circle aids/tools are there where angles are doubled? [closed]

I was thinking back to my undergraduate degree and remembered Mohr's circle, where the angles on the circle are double what they are physically (only thing I remember from that course because of the ...
0
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1answer
26 views

Finding Acceleration Force of Gravity on Rotated Accelerometer

Is it possible to calculate the force of gravity on the $x$, $y$, and $z$ readings of an accelerometer if I know the rotation of the sensor? If so, how would I do this? Sorry if I am doing this ...
0
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1answer
27 views

Calculating Resultant Force and Torque

I'm working on a sandbox game that allows the player to build a spacecraft and attach thrusters in arbitrary locations on the hull of the spacecraft. The game is set completely in 2D. (I'm a ...
1
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5answers
138 views

Gravity doesn't seem to work the way it is supposed to [duplicate]

This has been a bit of an awkward question that's been plaguing me ever since I started watching space documentaries on discovery about 10 years ago. I was saving this for the day I would ever meet ...
1
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1answer
23 views

Degrees of Freedom for an Asymmetric top

How many degrees of freedom does an asymmetric top have if it is rotating about a fixed point?What are the generalised coordinates used then?
2
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1answer
73 views

Rotation from Goldstein's Classical Mechanics

I apologize for the ambiguity in my title. It was rather difficult to figure out what is the most appropriate title for my questions. My questions come from chapter 4 and chapter 5 of Goldstein, ...
2
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1answer
62 views

Why does this model fall apart when angular velocity is small?

I'm doing a physics problem in which a marble spins around a spinning bowl and both have angular velocity $\omega$. It rotates with radius $r$ around the central axis and the hemispherical bowl has ...
2
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2answers
58 views

Why do rotations of a multicomponent state function take this form?

I am reading Leslie Ballentine's Quantum Mechanics, section 7.2, which is all about the explicit form of the Angular Momentum operators. I understand how he gets the form for the single component ...
1
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1answer
30 views

How do I calculate motor efficiency from voltage, current and RPM?

I have a setup where a motor is spinning at a constant (known) RPM, under no load. I know the power going into the motor (voltage * current), and I can find out the rotational kinetic energy of the ...
1
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3answers
66 views

Is there a difference between “average acceleration” and centripetal acceleration?

Question adapted from Examkrackers MCAT prep book: A particle moves along a half circle (diameter=$10\text{ m}$) at a constant speed of $1\text{ m/s}$. What is the average acceleration of the ...
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2answers
53 views

What point of application of force ensures more acceleration in a rod?

Suppose there is one rod and a force F is applied in two cases: Case 1: exactly at the middle on center of mass Case 2: at one end of rod In which case would the center of mass of rod be accelerated ...
2
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2answers
183 views

Rotation of Taylor expansion of a scalar

I have a scalar magnetic field in a volume expressed by the formula $$B(x,y)=B_0 + \frac{\partial B}{\partial x}(x-x_0) + \frac{\partial B}{\partial y}(y-y_0)$$ which approximates the ...
3
votes
1answer
51 views

Rotating hoop with fixed body inside of same mass [closed]

Please help me to solve this problem. I am unable to understand which force will cause the hoop to bounce. A small body $A$ is fixed to the inside of a thin rigid hoop of radius $R$ and mass ...
1
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2answers
96 views

A simple way of calculating Euler Angles from Rotation Matrix — help!

This is a follow up of this question : I have the rotation matrix $$ \left( \begin{matrix} a_{11} & a_{12} & a_{13}\\ a_{21} & a_{22} & a_{23}\\ a_{31} & a_{32} & ...
1
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2answers
56 views

Euler angles derivation

I have been trying to grasp the idea of Euler angles for a while. Can anyone point out if my understanding is correct or not. Situation: We have 3 axes known as principal axes of inertia which define ...
0
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2answers
57 views

Rotational behavior of objects in zero-g with forces [closed]

I would like to know how this object would rotate in free space out of curiosity. Below is a diagram of the object. It is of uniform density and has a center of mass in the center of the object, ...
1
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0answers
33 views

what does exactly accelerometer measure on a vertical rotating disk?

I am trying to understand an aspect of rotational dynamics. I am having some trouble arriving at a solution. Consider a disk of uniform mass distribution, and radius R centered at the origin of an xy ...
10
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2answers
198 views

Understanding the “$\pi$” of a rotating disk

Let us say you are in an inertial reference frame with a circular planar disk. If you take your meter measuring rods (or perhaps tape measure) you can find the diameter and circumference of the disk. ...
1
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1answer
100 views

Accelerometer problem - difficulty understanding my readout

I am having great difficult understand my readout from an accelerometer that I placed on a rotation wheel. The wheel spins at various speeds and i measured the radius from the center. I think I ...
1
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2answers
97 views

What happens if the earth stops rotating? [duplicate]

I was wondering what would happen to all the components on the surface of the Earth if the Earth suddenly stops rotating but does not stop revolving.
7
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1answer
689 views

How to calculate roll, yaw and pitch angles from 3D co-ordinates (Euler Angles)

I have digitized a video of a flying fly in a 3-dimensional space. At all instants I know the x, y, and z co-oridinates of the following points on the fly's body --- The points are my choice, and ...
1
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1answer
45 views

A pretty dumb question on observation

Very often I have seen, that a bicyclist can balance himself better, while in motion, than he can while at rest(with his legs on the paddles of the bicycle). Now, I know that objects, say, a disc ...
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4answers
134 views

Sun revolves around the Earth [duplicate]

What if somebody says that Sun revolves around the Earth and not Earth revolving around the Sun? What would be the consequences?
0
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0answers
18 views

Pseudo force in rotational motion?

If a cylinder is in combined rotation and translation on a moving surface(say a plank with some acceleration), while solving for the acceleration of the centre of mass of the cylinder, do we consider ...
1
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1answer
37 views

Could someone explain the “revolving frame” to me, as it is used in basic NMR?

I am an undergrad intern at a national lab currently working with a basic proton NMR device. The device consists of two big coils which provide the static magnetic field, and a smaller coil, which ...
0
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1answer
51 views

What are phase conventions in angular momentum and rotation calculations?

I work with complicated angular momentum calculations related to atomic physics; nevertheless, I never need to use anything related to a phase convention (apparently because it's taken care of in a ...
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2answers
55 views

Kinetic energy of a mass rotating about two axes

I'm working on a question where I have to find an equation for the kinetic energy of a mass being rotated by a fold-able arm. The equation for $m_1$ is obvious, however, the equation I derived for ...
22
votes
5answers
4k views

Artificial gravity on rotating spaceship?

One of the possible ways to simulate gravity in outer space is to have a rotating spaceship, so that the centrifugal force experienced provides a gravity-like force. My question is: shouldn't this ...
0
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3answers
94 views

Geostationary orbit and rotation speed of a planet

Assume for planets similar to Earth but with different rotation speeds (including zero), and we put a satellites at altitude of 35 786 km/hr (similar to the Geostationary orbit or earth), with speed ...
4
votes
2answers
70 views

Do Baryons have Quantized Vibrational and Rotational States?

Given that baryons are not point particles but are composed of three quarks, are there quantized vibrational and rotational states analogous to those of molecules? If not why not, and if so are ...
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0answers
46 views

When rotating a liquid-filled jar what determines how much force goes to spinning the specimen floating inside?

Another way of stating it: When you have leaves in a (cylindrical) tea cup, if you rotate the cup (eg clockwise), the leaves largely stay in place relative to the table, but spin clockwise a little. ...
2
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4answers
91 views

Do these cars rotate on themselves?

I was reading about the moon rotation around earth and the tidal lock related. I found some interesting information already here and on astronomy.stackexchange.com as well. The moon is known to have a ...
2
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0answers
69 views

Find the exact angle as a function of time for a rod that swings on a frictionless axle

This is a simple problem I thought of that I haven't been able to solve. Given a rod of uniform mass attached to a fixed axle, find the angle it makes with the horizontal if it is dropped from rest ...
2
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3answers
82 views

Is it possible to extract energy from mass rotating in space?

Consider a single isolated rotating mass (for example planet), is it possible to extract energy out of its rotation? If yes, how could that theoretically be achieved?
0
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1answer
73 views

Is sun revolving around certain mass in space with reference to some other galaxy?

Every planet and satellite revolves around their mother planet and about their own axis as we know. So they are compacted as a system. Then why not sun?
2
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1answer
58 views

Deriving Rabi rotation matrix

I want to understand where the matrix: $$ \left|\psi(t)\right> = \binom{a(t)}{b(t)} = \begin{bmatrix} cos(\Omega t/2)&-ie^{i\phi_L t}sin(\Omega t/2) \\ -ie^{-i\phi_L t}sin(\Omega t/2) & ...
0
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1answer
40 views

Torque required to rotate panel on one axis

I am working on a project that requires solar panel to rotate around its axis, but I am struck with deciding the specs of the Servo Motor that is capable of doing this. Though, the panel hangs on its ...
-1
votes
1answer
119 views

Calculating pitch and roll with accelerations greater than +/- 1g

I'm looking to compute the pitch and roll of a device fitted with a three axis accelerometer when it is not at rest or moving at a constant velocity. Most applications I've seen so far are for ...
1
vote
1answer
519 views

Explaining the restorative force in a bifilar pendulum

Ok so I am an A2 physics student, and for one of my pieces of coursework I conducted a practical investigation, my topic being the factors affecting the period and swing of a bifilar pendulum. The ...
0
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1answer
66 views

When does the angular momentum point in a different direction from the angular velocity?

I read this somewhere: $$\mathbf{L} = \tilde{\mathbf{I}}\mathbf{\omega}$$ In general, the angular momentum vector, $\mathbf{L}$, obtained from Equation above, points in a different direction to the ...
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3answers
427 views

Derivation of the general Lorentz transformation

The standard Lorentz transformation or boost with velocity $u$ is given by $$\left(\begin{matrix} ct \\ x \\ y \\ z \end{matrix}\right) = \left(\begin{matrix} \gamma & \gamma u/c & 0 & 0 ...
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0answers
73 views

2d pool collision with rotational motion

I'm trying to calculate two 2d disks' collision with rotational motion. The collision is perfectly elastic: the sum of translational and rotational energy is conserved. In the instant of the collision ...
-1
votes
1answer
56 views

Can a solid Au nanoparticle rotate (i.e., spin) in a vacuum?

I think there are two cases, if it has an initial angular velocity, then it is supposed to rotate. If its initial angular velocity is zero, then the particle would not rotate. However, should a solid ...
0
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0answers
74 views

Derive time difference of phase rotated wavelets

I have one question concerning phase rotation of signals and I am not sure wether it works or not: Let's assume we have a zero-phase wavelet x(t) i.e. Ricker wavelet. Unfortunately, in our ...
9
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4answers
2k views

What is the cause of centripetal/centrifugal force?

What is the cause of centripetal/centrifugal force? When an object of mass $m$ is moved in a circular orbit, it experiences a centrifugal force radially away from the center. What is the cause of this ...
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0answers
61 views

Rotation motion like the number 8

I'm a college student majoring in culinology and I'm trying to find out the reason or method of the number 8 motion. Responses doesn't have to be in culinology examples, but that would be a great help ...
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0answers
68 views

Rotate the phase of a wavelet

Let's take a zero-phase Ricker wavelet which is given by: $$ \psi(t)=\frac{2}{\sqrt{3\sigma}\pi^{1/4}}\left(1-\frac{t^2}{\sigma^2}\right)e^{-t^2/2\sigma^2} $$ in the time domain which is often used ...