A specific reference frame that describes its coordinates in a manner that does not depend on time and is isotropic.

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6
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2answers
82 views

Will accelerated observer see radiation from the charge that is at rest in observers's frame?

So I had a huge debate about this with my friends. Imagine that you are in a non-inertial frame of reference. For simplicity, assume that frame is accelerated along x-axis. You have held a charge in ...
1
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1answer
50 views

Relativistic transformation of electrical current [on hold]

If, in frame $S$, we have an electrically neutral wire with some current $I$, modelled as positive charges moving in $x$ direction and negative charges moving in $-x$ direction, then how would one ...
1
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0answers
16 views

How to prove that the Einstein velocity addition is a one-parameter composition formula of a one parameter group? [duplicate]

How to prove that the Einstein velocity addition is a one-parameter composition formula of a one parameter group?
-4
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0answers
38 views

How did the Michelson-Morley experiment really confirm the universal speed of light? [on hold]

So we know the earlier physicists largely assumed light moved in the aether as a fixed reference frame, and the Michelson-Morley experiment successfully disproved that. But it appears that the ...
20
votes
5answers
3k views

Is it possible to stay up while riding a bike on a moving sidewalk without actually moving?

If I ride a bicycle on a moving sidewalk so that I am not in effect moving at all relative to the ground, will I fall over?
1
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0answers
76 views

The path that a light beam takes in empty space

First excuse me if this question is very simple for you but for me and for my friend is not. Recently we were discussing what path a light beam will follow in a box moving at a constant velocity in ...
1
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1answer
40 views

Time variable in Lorentz transformations

When an object goes with a speed near from the light celerity, it inflates in the direction of its speed. The inflation rate is given by Lorentz transformations as follows: $x'= γ(x-vt)$ where $v$ ...
1
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1answer
82 views

Derivation of Lorentz Transformations

How can I derive the Lorentz transformations? I don't want to use hyperbolic functions and the fact that the light waves travel by forming spherical wavefronts. Is there a way to derive the Lorentz ...
-2
votes
2answers
87 views

How can we know that the speed of light is constant?

Science say that within a constant time frame the light travels a constant distance. But if time is relative how can it be possible to use it as a reference to say that something is constant?
0
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1answer
27 views

Is it true that the free body cannot remain at rest in inhomogeneous and anisotropic space?

In the page 5 of which Mechanics by written L.D.Landau, this book said "If we were to choose an arbitrary frame of reference, space would be in-homogeneous and an-isotropic. This means that, even if a ...
2
votes
2answers
222 views

How is 4-current a 4-vector?

I am looking at Jackson sec 11.9, where he states that the $\rho,\bf{J}$ form the 4-current $$J^\alpha=(c\rho,\bf{J})$$ Jackson says this is from the invariant of the 4-divergence $\partial^\alpha ...
0
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2answers
115 views

How to interpret Hermann Minkowski's comments on the construction of spacetime

What did Minkowski mean by his statement: "The views of space and time which I wish to lay before you have sprung from the soil of experimental physics, and therein lies their strength. They are ...
1
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2answers
91 views

Why does Special Relativity apply to more than just light?

It is my understanding that time dilation is derived from the constancy of the speed of light in vacuum. I would assume this implies that the quirky consequences would therefore apply only to light. ...
3
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2answers
52 views

Pole and Barn Paradox w/ Spacetime Interval

I'm having trouble with a pole and barn paradox problem. The problem is as follows: A pole vaulter is running with a pole at $ v=\frac{\sqrt3}{2}c $. Her pole has a proper length of $L$. She runs ...
1
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1answer
46 views

Does curved spacetime arise from inhomogeneity of gravitational field?

In general relativity textbooks such as Sean Carroll's Spacetime and Geometry, there is often a line of reasoning that goes like this: Strong equivalence principle states that free falling frames ...
3
votes
1answer
72 views

Homogeneity and isotropy and derivation of the Lorentz transformations

In deriving the Lorentz transformations I have found (from reading a few different sets lecture notes) that it is argued that they must be linear and thus there general form must be $$x'=Ax+Bt,\quad ...
0
votes
0answers
27 views

Inertial coordinate systems [duplicate]

In Newtonian mechanics, by the following two assumptions: (i) The time is absolute. (ii) The length is absolute. it is easy find the relations betweem two coordinate systems with uniform motion ...
1
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2answers
75 views

Definition of the Lorentz transformations [closed]

Until very recently I believed that the Lorentz transformations were defined as "the transformations that carry one inertial reference frame into another". In Wikipedia's page we find something along ...
2
votes
1answer
47 views

An example of a theory that respects the Weak Equivalence Principle but violates the Einstein Equivalence Principle

The Weak Equivalence Principle has any one of the following forms: the inertial mass is equal to the gravitational mass there exists a preferred class of trajectories through spacetime, known as ...
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votes
1answer
30 views

Newton's 2nd law for rotation (accelerated rolling and inertial frame of reference) [duplicate]

I need help in understanding why, in accelerated rolling, the center of mass must be at the origin of an inertial frame of reference in order for the second law to be applicable. Thanks!
4
votes
2answers
115 views

Two inertial frames (different angles)

The motion of the earth relative to a star changes the angle at which the star is perceived. Consider to inertial frames of reference I and I'. I' moves with velocity w relative to I along the ...
0
votes
1answer
37 views

Coordinate Transformation in Classical Mechanics

The coordinates in one inertial frame are represented by $(x,t)$. Under coordinate transformation, the coordinates in another inertial frame can be represented by $f(x(t),t)$. It can be shown that the ...
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2answers
52 views

Does the constancy of the speed of light in vacuum hold for any observer in GR as well?

From SR, we know that the speed of light in a vacuum is the same for all observers, regardless of the motion of the light source. But in GR, does it still hold for all observers? I mean the constancy ...
0
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0answers
21 views

Gallilean Transformations with Linear Acceleration

I'm wondering if it is possible at all to use Galilean transformations to simplify this problem. Consider two massive objects (Objects A and B) in space. The two objects are attached via a spring ...
2
votes
2answers
70 views

Twin paradox in special relativity: length contraction

Can the concept of twin paradox be applied to length contraction as well? meaning that the twin which is in spaceship will have its meter rod "actually" contracted while he will see his brother's ...
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1answer
52 views

Which reference frame decides the relative velocity of two reference frames?

The following thought experiment is often used to introduce Special Relativity: The thought experiment fails to specify which reference frame establishes $\vec{v}$--the observer on earth or the ...
4
votes
0answers
39 views

Why rotating reference frames are not inertial? [duplicate]

Let's say I'm standing on the equator, and that there is no other reference point in the sky. If the planet is rotating, then I measure my weight to be lower than if it is not. But given that I have ...
0
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1answer
29 views

Earth, Sun and beginner's reference frames

In the post-Newton era, where "absolute space" is not absolute, how is the reference frame in which "the Earth moves round the Sun" accurately defined?
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0answers
43 views

Galilean transformation of Schrodinger equation and momentum operator

Let $$ \left.\begin{aligned} t'&=t\\x'&=x-vt \end{aligned}\right\} \quad \Longrightarrow\quad \dot{x}'=\dot{x}-v $$ and therefore $p'=p-mv$. If $p'=-i\hbar\nabla' $, then ...
0
votes
3answers
68 views

Direction of deflection of Coriolis force on Earth

I'm a bit confused about Coriolis force direction on Earth. The observed deflection is to the right in the northern emisphere and to the left in the southern one. But what about an observer in the ...
1
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1answer
82 views

How is time dilation consistent between both observer?

There is a special variant of time dilation paradox bugs me. Imagine there are 2 small spaceships moving toward each other in constant speed. Each ship has an observer on-board. According to both ...
0
votes
1answer
38 views

Coriolis object deflection and conservation of angular momenutum

I'm trying to understan kinematic inertial explanation of the apparent deviation of objects due to fictitious forces in rotating Earth. Take an object moving from the equator northwards, or ...
0
votes
1answer
27 views

Synchronization of clocks

I have read the book "Introduction to special relativity " by Robert Resnick In the book I have found that "If the distance between the clocks is L, one observer will see the other clock lag his by ...
0
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2answers
135 views

Meaning and logic of Einstein's train thought experiment

This seems to be a recurrent topic but I wasn't able to find any satisfactory discussion about this tought experiment. I will quote the original story from Einstein's and put my doubts inside: Up ...
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votes
1answer
61 views

How time and speed of light are related? [closed]

I want to know how speed and light and time are related? How will motion with highspeed effect time? I am not a physics student. I want an answer which is free of mathematical relations. I want an ...
0
votes
1answer
30 views

Deviation of free falling objects (Coriolis effect) using conservation of angular momentum

I read this pdf damtp.cam.ac.uk/user/stcs/courses/dynamics/lecturenotes/section4.pdf on non inertial frame, in particular I have a question on the deviation of free falling object due to Coriolis ...
0
votes
1answer
28 views

Multiple Objects at Constant Speed

Imagine 1 million objects travelling in space, at a constant speed, along an imaginary line. They don't deviate from that line for the sake of this argument. Now, object 1 has a velocity of $v_{1}=1$ ...
4
votes
2answers
77 views

The two causes for the factor 2 in Coriolis effect

While reading this document on Coriolis effect http://empslocal.ex.ac.uk/people/staff/gv219/classics.d/Persson98.pdf, I saw the followig sentence Two kinematic effects each contribute half of the ...
7
votes
3answers
168 views

Coriolis force and conservation of angular momentum

I'm trying to understand the relations between the existance of Coriolis force and the conservation of angular momentum. I found this example on Morin, which confuses me. A carousel rotates ...
5
votes
0answers
129 views

Can special relativity be derived from the invariance of the interval?

As far as I know, the classical approach to special relativity is to take Einstein's postulates as the starting point of the logical sequence, then to derive the Lorentz transformations from them, and ...
0
votes
2answers
375 views

How to achieve speeds faster than light? [duplicate]

So, I heard that all speed is relative. And that nothing can travel faster than light. Then I guess it is OK for a spaceship to leave Earth at 0.6c constant speed. And what if an other spaceship were ...
0
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1answer
29 views

Effect of Coriolis force

Is Coriolis force fictitious in an inertial frame or not? If so can it be mathematically deduced using an inertial frame as reference?
0
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0answers
72 views

Derive Galilean transformation. (The meaning of the relativity)

In the book The meaning of the relativity Einstein says that in classic mechanics two postulates are previously supposed: 1.- The time is absolute. 2.- The longitude is absolute. And this implies ...
0
votes
1answer
32 views

Some questions about forces

If I am sitting inside a closed sphere (I can't see the outside), can't I feel when the sphere is at constant speed ? Can I feel when it is accelerating ? Why ? The defination of force given ...
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2answers
59 views

Is it always possible for an observer to realize to be in a non-inertial frame?

Galilean relativity principle states that two frames moving with uniform linear motion cannot be distinguished. But is it always possible to realize to be in a non-inertial frame? In a rotating frame ...
0
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3answers
53 views

Physical interpretation of Coriolis terms in acceleration

Consider a reference frame which is rotating (for example on a carousel) and a steady inertial frame, with the same origin. $\vec{r}=\vec{r'}$ $\vec{v}=\vec{v'}+\vec{\Omega}\times\vec{r'}$ ...
3
votes
2answers
517 views

Is Newton second law covariant or invariant?

Is Newton second law covariant or invariant between two inertial frames, moving with uniform traslational motion with respect to each other? If it is invariant then, indipendently from the frame, ...
0
votes
0answers
26 views

Value of $E_x$ through an $X-\textrm{boost}$

Suppose I'm standing at the (0,0,0) point of a coordinate system and I see an electric field where $E_x=f(t,x,y,z)=\sin(x\cdot y\cdot z\cdot t)$ and at time $t_0=0$ I start moving on the x-axis at ...
1
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0answers
44 views

Electromagnetic Tensor under Lorentz transformation, $F'(\Lambda x)= \Lambda F(x) \Lambda^T$?)

Suppose we have a configuration of electric and magnetic fields $E(x1,x2,x3,x4)$ and $B(x1,x2,x3,x4)$, they depend of position and time for a fixed coordinate system. And I want to know how someone in ...
5
votes
2answers
965 views

Does rest exist?

I initially thought that the concept of rest depended on an inertial frame of reference. So for example, if the Earth and everything on it were the only things in the universe, and the Earth was ...