The inertial-frames tag has no wiki summary.
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When we talk about speeds in relativity theory, where are they measured?
I recently asked a question here about if the direction we travel matters in relativity theory:
Does it matter in which direction I travel in relativity theory?
After I got answers and making more ...
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8answers
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What is the Earth truly rotating about/revolving around?
Earth rotates on its axis and revolves around the sun, the sun revolves around the galaxy, the galaxy is also moving. So Earth's net rotation as observed from a fixed inertial frame consists of all ...
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8answers
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Proof that the Earth rotates?
What is the proof, without leaving the Earth, and involving only basic physics, that the earth rotates around its axis?
By basic physics I mean the physics that the early physicists must've used to ...
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3answers
102 views
Newton's First Law of Motion; Empirical Aspects
Newton's first law states that in an inertial frame, a body at rest continues to be at rest, and a body in constant rectilinear motion continues its motion, unless an external force is applied upon ...
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1answer
104 views
The definition of Lorentz transformation
I know that the Lorentz transformation, when two frames $\mathcal{S}$ and $\mathcal{S}'$ are in standard configuration (the axes are all parallel to their counterparts in the other inertial frame) is ...
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1answer
77 views
A physical sense of an Inertial frame
Definition clarification needed, please: I am hoping to get physical sense of an "inertial frame".
Do inertial reference frames all have zero curvature for their spacetime?
So is an inertial frame ...
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3answers
126 views
How to create frame of reference?
Is this possible to create a inertial frame of reference in the earth?
How it is possible?
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2answers
106 views
How big is an inertial frame?
How big is an inertial frame?
Consider a huge rod which is rotating about a fixed point in a plane, its length is 1 light year.
Thus light from its end closer to the fixed point to the end farther ...
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0answers
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Determining Ether Drag - Aberration of Starlight
In order to determine the relative motion between the Earth and the ether (the medium through which light supposedly propagated. It has zero density and complete transparency), scientists used the ...
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0answers
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does a rotating moving body in “flat” space curve its path because of frame dragging?
I am not a physicist.
let's say we have a space with an object in it, where all other gravitational bodies are so far away that their affect on the shape of the space is negligible.
let's say the ...
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6answers
202 views
Inertial Frames of Reference - Inertial vs. Accelerated Frames
According to Robert Resnick's book "Introduction to Special Relativity", a line states the following as the definition of an inertial frame of reference: "We define an inertial system as a frame of ...
0
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2answers
111 views
Inertial Frames of Reference - Description of an Inertial Frame of Reference
An inertial frame of reference is described as being a frame of reference in which the first law of Newton (the law of inertia) holds. This means that all events as described with respect to this ...
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2answers
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Foucault pendulum
The equations of motions for a Foucault pendulum are given by:
$$\ddot{x} = 2\omega \sin\lambda \dot{y} - \frac{g}{L}x,$$
$$\ddot{y} = -2\omega \sin\lambda \dot{x} - \frac{g}{L}y.$$
What are the ...
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2answers
81 views
Reality error and relative velocity
Suppose a person is walking in rain carrying an umbrella. He is tilting his umbrella at some angle with the vertical so as to protect himself from the rain. But a neutral observer who is standing ...
2
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2answers
172 views
Fictitious forces confusion
I have a hard time understanding the subject of fictitious forces. Let's discuss a few examples:
1) I'm sitting inside a vehicle which is accelerating in a straight line. I feel like someone is ...
3
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2answers
177 views
Second law of Newton for variable mass systems
Frequently I see the expression
$$F = \frac{dp}{dt} = \frac{d}{dt}(mv) = \frac{dm}{dt}v + ma,$$
which can be applied to variable mass systems.
But I'm wondering if this derivation is correct, ...
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0answers
28 views
Why does the local inertial compass coincide with the stellar compass?
I found this physics paper via a non-duality site and I wished that I could understand it. Could someone please either read it and explain it to me or else point me to pages that would help me ...
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2answers
61 views
Why does isotropy principle require existence of inertial transformation when axes are reversed?
Assuming one spatial and one termporal dimension, let's assume an intertial transformation $A(v)$ as follows:
$$
\begin{pmatrix}
t' \\
x' \\
\end{pmatrix} = A(v)
\begin{pmatrix}
t \\
x \\
...
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4answers
356 views
The definition of an inertial reference frame in Einstein's relativity
I'm reading Sean Carroll's book on general relativity, and I have a question about the definition of an inertial reference frame. In the first chapter that's dedicated to special relativity, the ...
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1answer
109 views
Accelerating expansion of universe - entire universe a non-inertial frame of reference?
If the expansion of the universe is accelerating, doesn't that mean that the entire universe is a non-inertial frame of reference? And if so, what implications does this have (if any)?
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1answer
268 views
Problem with convergent geodesics at 2D sphere
There is a chapter on general relativity in the book Spacetime Physics Introduction To Special Relativity by Taylor and Wheeler, which qualitatively explains how attractive gravitational force can be ...
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2answers
252 views
What is the formal definition of a stellar day?
I'm having trouble understanding precisely what a stellar day is. Neither the USNO nor the IERS sites provide a definition. And Wikipedia's description as the "rotation period relative to the fixed ...
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1answer
129 views
Galilean relativity in projectile motion
Consider a reference frame $S^'$ moving in the initial direction of motion of a projectile launched at time, $t=0$. In the frame $S$ the projectile motion is:
$$x=u(cos\theta)t$$
...
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2answers
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Fictitious Forces $\overset{?}{⇔}$ Constraint Forces (re: D'Alembert's Principle)
Are fictitious forces and constraint forces the same thing?
0
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1answer
56 views
Proper notation when working with three Euclidean spatial coordinates in a setting with a time parameter
The How does the Euclidean metric is the symmetry group of Euclidean space. It includes rotations and translations.
Say I consider an Euclidean space and a time parameter. How does the Euclidean ...
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1answer
72 views
Is it best to look at light as a particle when trying to understand special relativity?
So my course about special relativity explains time dilation using a moving train, where one sends up (i.e. perpendicular to the direction of movement) a light pulse which gets reflected etc. (a ...
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1answer
114 views
Galileo's dictum and how light cannot violate it
Okay. So I've been told that the speed of light is constant and cannot violate Galileo's dictum, but even if it weren't constant (in a vacuum), how would it violate it anyway?
Say you are on a train ...
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2answers
245 views
Using Lorentz Invariance of Charge To Calculate Current Density
I'm attempting a problem from Zwiebach: A First Course in String Theory and am completely stuck. Could anyone give me a hint? The problem is as follows.
Consider $S$, $S'$ two Lorentz frames with ...
4
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1answer
257 views
Is momentum conservation for the classical Schrödinger equation due to non-relativistic or due to some more exotic invariance?
I had no problem appliying the Neothers theorem for translations to the non-relativistic Schrödinger equation
$\mathrm i\hbar\frac{\partial}{\partial t}\psi(\mathbf{r},t) \;=\; \left(- ...
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2answers
666 views
Does the speed of light vary in noninertial frames?
The speed of light is the same in all inertial frames.
Does it change from a non-inertial frame to another? Can it be zero?
If it is not constant in non-inertial frames, is it still bounded from ...
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2answers
94 views
Really basic mechanics and Galilean Relativity question
Consider two solid objects: A and B.
System 1:
A <----- B
10m/s
System 2:
A -----> B
10m/s
...
0
votes
1answer
75 views
In what subfields and how fare can the “naive limit” of special relativity be carried?
Even if many interesting similarities between the classical and the quantum mechanical framework have been worked out, e.g. in the subject of deformation quantization, in general, there are some ...
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3answers
310 views
The two faces of $F = m*a$
As I have understood,
$F(t)=m \cdot a(t)$
can have 2 different meanings:
When applying an external force $F$ on a point mass of mass $m$, the resulting acceleration of that mass at time $t$ is ...
2
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1answer
147 views
Why can we use just one angular velocity vector to describe the rotation of a whole non-inertial reference frame?
The other day in class the professor was explaining non-inertial reference frames. We were working out how to find the acceleration of a point as measured from the non-inertial reference frame, and ...
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4answers
434 views
How fictitious are fictitious forces?
How fictitious are fictitious forces?
More specifically, in a rotating reference frame i.e. on the surface of the earth does an object that is 'stationary' and in contract with the ground feel ...
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3answers
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Centripetal/Gravitational Force
Suppose a satellite is orbiting the Earth. The gravitational and centripetal force supposedly point towards the Earth. Therefore, the net force is towards the Earth. Since the satellite doesn't fall ...
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1answer
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The form of Lagrangian for a free particle
I've just registred here, and I'm very glad that finally I have found such a place for questions.
I have small question about Classical Mechanics, Lagrangian of a free particle. I just read Deriving ...
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2answers
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Deriving the Lagrangian for a free particle
I'm a newbie in physics. Sorry, if the following questions are dumb. I began reading "Mechanics" by Landau and Lifshitz recently and hit a few roadblocks right away.
Proving that a free particle ...
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2answers
564 views
Flying a toy helicopter inside an accelerating train
Scenario:
You ride in a train, you have this helicopter toy. The train is not yet running when you flew your helicopter on a constant altitude (say 1 meter above the train's floor).
Question:
What ...
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3answers
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Is acceleration relative?
A while back in my Dynamics & Relativity lectures my lecturer mentioned that an object need not be accelerating relative to anything - he said it makes sense for an object to just be accelerating. ...
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5answers
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Will a warm body naturally slowdown?
Suppose a warm body moving in an empty space with high speed.
The body emits radiation based on its temperature. The protons emitted forwards of the body will have higher energy due to Doppler shift ...
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votes
2answers
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Why is $c$ considered as the speed of the photons?
Maxwell equations brought $\ c_{o}=\frac{1}{\sqrt{\mu_{o}\varepsilon_{o}}}\ $.
Since this is a constant, it made all physicists at that time wonder where was the frame of reference?
They ended up with ...
3
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2answers
307 views
What is the inertial frame that explains the Foucault Pendulum?
I know that the Foucault pendulum rotation in relation to Earth is a proof that the object is inertial in relation to the distant stars. But what makes them more important than the Earth? Are they an ...
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2answers
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frames of reference [duplicate]
Possible Duplicate:
Help Me Gain an Intuitive Understanding of Lorentz Contraction
Frames k and k' are inertial frames. Frame k' is moving at a velocity of magnitude v relative to frame k ...
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4answers
244 views
Freefall in/out of an enclosed environment
I've just been learning about Einstein, relativity, and the equivalence principle in Physics. I'm fascinated with the idea of being inside a free-falling enclosed environment (such as, e.g., rocket, ...
2
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2answers
520 views
Earth-Centered Inertial (ECI) reference frame as approximate inertial frame of reference
In many practical applications, one can consider the Earth-Centered Inertial (ECI) reference frame approximately as an inertial reference system, though strictly speaking, it is non-inertial.
Is ...
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6answers
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Is there any true inertial reference frame in the universe?
Is there any true inertial reference frame in the universe?
Newton's first law states that an object at rest remains at rest, and an object performing uniform motion performs uniform motion, until ...
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1answer
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centrifugal force in static frame of reference
The other day we derived Kepler's third law.
$$
\left( \frac{T_1}{T_2} \right)^2 = \left( \frac{r_1}{r_2} \right) ^3
$$
In order to derive this, you can look at a given planet that revolves around ...
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4answers
754 views
Inertial frames of reference
I'm struggling with the notion of an inertial frame of reference. I suspect my difficulty lies with the difference between Newtonian and relativistic inertial frames, but I can't see it.
I've read ...
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2answers
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Galilean transformation in relativity
Assume flat spacetime in a general relativistic framework (or special relativity for that matter) and two observers $A$ and $B$, with non-vanishing velocity relative to each other. We know that they ...
