Frames Definition and 610 Threads

I study electromagnetism and I got to the chapter about special relativity, in this chapter my professor (since we are not using the electromagnetic tensor in this course) used a specific case to show that the electric field parallel to the velocity of a frame of reference stay the same in both...

So there are no "absolutely motionless" reference frames, but is there a set of reference frames which could be described as "absolutely rotation-less"?

Hello! Why do we need to impose a change on the basis vector, when going from a reference frame to another. I understand that the components of the vector and the basis change using inverse matrices (the components use a matrix and the vector basis the inverse). But the transformation condition...

Homework Statement The problem from Sterway, Jewett book. The Attempt at a Solution The answer in the book is something like 0,141 nm, as I remembered but I cannot achieve such answer coz' I cannot understand what actually asking, d is looks like a distance between two centers of the...

According to the Lorentz transformations, in the absence of gravity, the relations between coordinates of a primed system to those of a unprimed system are $$x'^{\ \alpha} = \Lambda^{\alpha}{}_{\beta}x^{\beta}$$ For the Lorentz invariance to be satisfied we must have...

Hi people, I have a question about the frame of references. Let's have an example: First case: Jill on rocket and Jack stationary on Earth. Jill moves relatives to Jack 0.6c (1.8*10^8m/s). The distance is 18*10^8m. At the zero time Jack and Jill synchronize their clocks. Then Jill starts to...

First I am not sure if this is the correct place to post this thread, but the thread will be about optics, quantum physics and special relativity, so it is a mixed subject. Please watch this video first: This technology allows capturing videos at mind blowing 1 trillion fps, which allows us...

Hello everyone, here I come with a question about inertial frames as defined in General Relativity, and how to prove that the general definition is consistent with the particular case of Special Relativity. So to contextualize, I have found that one can define inertial frames in General...

kuruman submitted a new PF Insights post Frames of Reference: Linear Acceleration View Continue reading the Original PF Insights Post.

A rocket is drifting in gravity-free space and is observed by an external observer who is also drifting at an unchanging location using an arbitrary coordinate system. The rocket accelerates at a fixed rate using a massless photon engine that results in a negligible change in the mass of the...

Ok I have a really basic question. Say you and I are floating in space and there is a single electron in front of us stationary to our frame of reference. Now I start hopping up and down. I see the electron accelerate up and down from my hopping frame of reference. I see a EM wave be...

Homework Statement Sonia walks up an escalator which is going up. When she walks at one step per second, it takes her 20 steps to get to the top. If she walks at two steps per second, it takes her 32 steps to get to the top. She never skips over any steps. How many steps does the escalator...

Uniformly accelerated reference frames in special relativity are represented in the space-like region of a lightcone as hyperbolae. These hyperbolae represent worldline of accelerated observers. However, there could not be be causal relationship between two events on the spacelike section...

Hi all - hope I'm not beating a dead horse here, but I'm following up on at least two other threads (made sense to consolidate): There are theories of quantum gravity (or the Standard Model Extension) that allow for local Lorentz violation. So, my first question: is there any reason why there...

Hello everyone, sorry if this is a noob question; I'm just starting out with special relativity. I was wondering whether relativity of simultaneity is a direct consequence of our ability to "know" being dependent on sight (light reaching a point). If, for example, we could only judge an event...

What determines whether a frame of reference can be considered stationary? I assume it is not allowed that the Earth be considered stationary and the universe is moving around it for example, as I would have thought that would lead to observation of faster than light movement. In...

What in the mathematics of the derivation of special relativity limits the model to inertial frames? How is an inertial frame defined in the context of the derivation?

Hello, I have a question regarding the following picture: Here, person B is moving in his S’ reference frame with a speed of u relative to Person A, who is in his reference frame S. An event shown by a star (*) happens after tA time according to A. The distance of that event is a distance...

From Chris' perspective Bob is traveling with 1.5*108 m/s in direction a. Angelica is also traveling with 2.4*108 m/s in direction a. From Bob's perspective Chris is traveling with 1.5*108 m/s in direction b (The opposite of x). Angelica is traveling with 1.5*108 m/s in direction a. They all...

kuruman submitted a new PF Insights post Frames of Reference: A Skateboarder's View Continue reading the Original PF Insights Post.

With a velocity dependent equation such as de Broglie's λ=h/mv There's just so many questions, where do I start... In your frame of reference, an electron might be standing still but from an outside frame it could be moving at 0.1c does that mean you'd see different wavelengths? What about when...

Homework Statement System S' moves with constant speed v=(vx,0,0) respect to the system S. On the S' system a particle moves with a constant acceleration a=(ax,ay,az). What is the acceleration a'=(ax',ay',az') measured from the system S?. Homework Equations Lorentz transformation The Attempt...

If yes then imagine what I am going to say... From a source two photons are emmutted symultaniously. If one of the photon had eyes to see what will 'he ' measures the velocity of the other photon which is moving with 'him'? Won't it be zero?!

My teacher just briefly introduced arc length parameterization and went on to frenet serret frames, without any explanation or motivation. What is the purpose of arc length parameterization? What role does it play in TNB? What is the purpose of TNB frames anyways?

Homework Statement The International Space Agency is designing a spaceship to reach the star Proxima Centauri, 4 cyrs (light years) away so that the on-board crew will age 4 years from departure to arrival. How fast must the ship travel? Homework Equations t(moving clock) = t(stationary...

Hi everyone, I did a search and couldn't find any useful information on frames and machines for statics (unless I missed it for which I apologize if I did) Does anyone have a few steps that they follow when setting up a FBD of a frame/machine. I'm having trouble being able to efficiently set up...

Think at a cop car with a siren that moves with a velocity Vc, it emits a sound with a velocity C Now think about a person that doesn't move, in front of the cop car, shouldn't he register that the speed of the sound emited is Vs= Vc+ C? According to the galileian equations (true for v <<c...

Homework Statement Consider an inertial frame S with coordinates ##x^μ = (t, x, y ,z)##, and a frame S' with coordinates ##x^{μ'}## related to S by a boost with velocity parameter v along the y-axis. Imagine we have a wall at rest in S', lying along the line x' = -y'. From the point of view of...

Homework Statement Two inertial frames S and S' are in standard configuration, the frame S' is moving along the x-axis of S with velocity v. In S' a straight rod parallel to the x' axis moves in the y' direction with velocity u. Show that in S the rod is inclined to the x-axis at an angle ##-...

It's said that, speed of light is same in every frame is reference. Consider an ideal situation, if I'm also moving at the speed of light, will I feel light to be at rest or still at the speed of light itself according to my frame of reference?

In Galilean Relativity, laws of mechanics are invariant across frames. In all the frames they are the same. So, in Dynamics and Relativity by W.D.McComb, it is written that this implies you cannot perform any experiment in an inertial frame that can tell whether an inertial frame is moving or...

Homework Statement At exactly 00:00:00 hours, a group of convicts escape from a planet in a space-ship that travels at speed ##v=\frac{4}{5}c##. After 11 min, a patrol spaceship goes after them with ##v_P=\frac{24}{25}c##. Ignore all acceleration periods. (i) The convicts immediately notice the...

Why is speed of light constant in all frames of reference. I don't understand.

I want to know why is the measurement of acceleration independent of inertial reference frames? I mean if displacement, velocity varies with change of inertial reference frames, acceleration should vary. And, one more question: When we say that displacement or velocity varies with change in...

Homework Statement Why do objects that have no external net force acting on them accelerate? Ex. If a ball is on an accelerating train, it will accelerate opposite the direction of the train's acceleration, assuming there is nothing blocking its path of motion and it is not strapped down. My...

Homework Statement You are in a car accelerating forwards. There is a baseball at your feet. Draw two FBDs showing the the ball's motion from the frame of reference of the car and the frame of reference of the sidewalk. Which frame of reference is non-inertial? In which frame do you observe the...

Homework Statement Classical Mechanics: John Taylor[/B] (1.27) The hallmark of an inertial reference frame is that any object which is subject to a zero net force will travel in a straight line at a constant speed. To illustrate this, consider the following experiment: I am standing on the...

is space an inertial or non inertial frame of reference?

As described in Wikipedia as well as this entry http://physics.stackexchange.com/questions/172739/is-the-lay-explanation-of-the-equivalence-principle-wrong, "being at rest on the surface of the Earth is equivalent to being inside a spaceship (far from any sources of gravity) that is being...

Under SR, we can talk about inertial frames that apply globally. However apparently, under GR, this concept only applies locally, because it breaks down on larger scales. Can anyone provide an explanation as to why this is? Is this due to the fact that space-time is warped in GR?

Thinking and reading about the twin paradox recently, I encounter a lot of explanations and resolutions that don't make sense to me. At its most basic, the issue is- when two bodies are in different frames of reference, why shouldn't relativistic effects affect both equally, negating time...

Hi, So apparently electrons don't orbit the nucleus of atoms so I'm assuming the lack of movement means that no energy from the atom is radiated away from an atom due to minuscule gravitational waves, over the life of the universe. But gravitational waves have got me thinking about reference...

Homework Statement I'm finding this very hard to get my head round! There's earth, and a star which is 6ly away, in the same reference frame. A starship sets out from the star, and another ship leaves Earth at the same time. Each one has ##v=0.6c##. What is the relative speed of the starship as...

I understand that if someone is traveling away from Earth at a very high speed, time will slow down for the traveler relative to the people on earth. However, why is it not the other way around? If there is no universal reference frame, could this situation not also be thought of as the traveler...

To simplify my question I would like to use a random example (although, the issue holds regardless of the numbers you pick). Suppose two objects collide (head-on) in one dimension. The initial parameters are as follows (units are irrelevant): m1=1;m2=2;u1=3;u2=-4; Also, suppose that exactly...

I had this questioning about the light clock on another thread, and DaleSpam suggested that I open my own thread, so here it is. I was asking if the light clock mind experiment was not contradicting the reference frame principle. I added that to my drawings: And DaleSpam answered this: So...

If a train is moving towards two simultaneous flashes and is equidistant from them, they will be seen to be simultaneous. Meanwhile a stationary footbridge observer watching the same train approach, also sees the flashes as equidistant, therefore simultaneous. Can someone explain how observers...

I wanted to check my understanding of momentarily co-moving inertial frames, so I came up with this example: Consider an inertial frame (with unprimed coordinates), about whose origin a clock moves in a circular path with constant speed, ## v ##. What is the time elapsed on the moving clock...

OK, I'm sure I'm just not thinking about this the right way, so please point out my simple mistake. Imagine a charged particle and 2 observers. Observer S is stationary relative to the charged particle, so sees no magnetic field from it. Observer A moves back and forth in front of the...

Claim: The acceleration (both direction and magnitude) for any object is the same in any inertial reference frame. Is this claim true? I think it is, but someone mentioned to me that time may be an issue as it's not agreed upon in all inertial reference frames. I'd appreciate any references...