Frames Definition and 610 Threads

What is the criteria to see the latest state of some object which exists after all the previous states in other reference frames? For instance, one observer may see a plane coming off the airport as 'present', other may see 'its flying' as present, but what is the criteria of those reference...

Hey everyone, I started reading up on GR a couple of days ago, and I'm somewhat stuck on the concept of a free-falling IRF. I understand that an observer on a free-falling small spaceship would experience the laws of physics in a rather simple form, eliminating the need for a force of gravity...

Homework Statement ds^2 = g_{tt} dt^2 + g_{tx} (dt dx + dx dt) with g_{tt} = -x and g_{tx} = 3 "Show that this is indeed a spacetime, in the sense that at every point, in any coordinates, the matrix g_{\mu \nu} can be diagonalized with one positive and one negative entry. Hint: You...

There is something that bugs me about inertial frames. According to Einstein's definition (chapter 4 of "Relativity"), an inertial frame is one for which Newton's first law holds: "a body far enough removed from other bodies continues in a state of rest or uniform motion in a straight line." He...

Hello I am having problems in GR because I do not understand how observations frames work in this theory. I have a few more specific questions. -In the schwarzschild metric, which frame is the metric written in? (The one with swarzschild coordinates) -In the non-vaccum solutions, how do we...

how to find support reactions in frames

I got stuck going over the derivation of fictitious forces in rotating frames. see specifically http://en.wikipedia.org/wiki/Rotating_reference_frame#Time_derivatives_in_the_two_frames this page to see the proof I'm talking about (sorry i'd love to be able to explain it by myself but...

Is it ok to formulate the postulates of SR like so: 1) If two reference frames are in a constant rectilinear motion relative to one another, then the laws of physics take the same form in both of them. 2) If two reference frames are in a constant rectilinear motion relative to one another...

Homework Statement What is the velocity of the plane where clocks in two different frames are synchronized? Homework Equations Lorentz Transformations: t' = γ(t - vx/(c^2)) x' = γ(x - vt) Solution should be v(t = t') = (c^2)/v * (1 - 1/γ) The Attempt at a Solution I am getting the...

Suppose we have two frames of reference, with one being accelerated (not inertial). This could be you standing on the platform of a train station as a train in front of you is starting. From the train's point of view, you are accelerating, but one obviously knows that it is actually the train...

someone please help me out with this question: You are in an elelvator that is able to travel up and down a mineshaft. a load is hung from the ceiling inside the elevator on a massless string. You find that the tension in the rope is 10% less than that of the weight force of the load. what...

My understanding is that as I move, from my FoR all objects and space itself (according to Einstein) contract along the direction of my movement. This length contraction occurs for all space and objects in front of me for an infinite distance. Furthermore, relative motion is relative, and the...

My question regards how the approximation becomes an equality.

Homework Statement Is the kinetic energy of an electron the same in all frames of reference? Homework Equations I think that the kinetic energy of an electron is E = hc / λ. However, I am not sure: I got this from searching Google rather than learning it myself. The Attempt at a...

So sense speed is relative, could I observe something traveling faster than light? Like in a car, when I see oncoming traffic it appears much faster, so could I not be traveling at, say 1/2c and observe somebody approaching at 1/2c therefore moving at 1c relative to me?

my exploration of relativity followed by first reading various books which failed to explain to me how relativity worked but built a strong feel of how one can think about it. after which i decided to take the mathematical way of understanding it for which i am going on with the prof susskind's...

Homework Statement In the laboratory frame, event 1 occurs at x = 0 light-years, t = 0 years. Event 2 occurs at x = 6 light-years, t = 10 years. In all rocket frames, event 1 also occurs at the position 0 light-years and the time 0 years. The y- and z- coordinates of both events are zero in...

Homework Statement K mesons (“kaons”) are unstable particles composed of a quark and an antiquark. They can be produced copiously in energetic collisions between stable particles at accelerator laboratories. Soon after they are produced, kaons decay to lighter particles. One type of kaon...

Hi, I am reading in some books that after the \beta-decay of neutrons, the maximum energy of the resulting electron is a bit less than 800 keV. In some cases, however, I see that in e.g. some studies that try to extract the electron energy from \beta-decay of neutrons with some Monte Carlo...

Homework Statement Suppose you have a spaceship and in the spaceship is a block on an frictionless incline. Initially, the spaceship is at rest on the Earth's surface. The astronaut in the spaceship observes the block sliding down the incline with acceleration Mgsinθ . Now consider that the...

What is an inertial reference frame?How are positions,velocities and accelerations changed when switching between different inertial reference frames? r=rx i + ry j + rz k Inertial reference frame:It is a frame of reference where Newton's laws of motion is valid.No fictitious...

I know total energy is conserved, but does this mean that different frames agree on the total energy of a particle? I'm assuming they don't agree on energy, because if I measured the total energy of a particle moving relative to me (which would equal the rest energy plus its kinetic energy)...

Lorentz factor for moving inertial reference frames is λ = \frac{1}{\sqrt{1 - \frac{v2}{c2}}}, where v is the relative velocity between the frames. But in my textbook (I'm only just learning relativity), it says the Lorentz factor for a particle is λp = \frac{1}{\sqrt{1 -...

can inertial reference frame ever have "lenght contractions" in 3d or in rest? hi! thank you for all answers in this topic in previous threatin same topic. i open this new thread in same topic but here i try to keep the issue here very short and readable , with no speculation and concentrating...

I'm not entirely sure how to treat non inertial frames in the lagrangian formulation, do the normal rules still apply?

I have often thought about how the one-way speed of light can be measured without having to use synchronized clocks, which tends to be controversial because the clocks are normally synchronized by using one-way light in the first place. Recently, Don Lincoln of Fermi-Lab suggested a method to...

Homework Statement Particle track detectors are used to measure the speed of particles if the lifetime of the particle is known. Particle X has a lifetime of 256.2 ps. These particles are created in an experiment inside the detector by a given reaction. The particles leave 21.8 cm long tracks...

Hello everyone, this is my first question here. I'm a mathematics student (actually pure math), but have recently found myself interested in learning about physics. I've started reading Introduction of Special Relativity by Rindler; I actually have no background in mechanics or basic physics...

Hi, In the classical theory, there is an absolute rest frame, and every frame moving with constant velocity with respect to it is called inertial frame of reference. The frames that are accelerating with respect to it are called non inertial. To test whether a frame is an inertial, we test...

Homework Statement a)Suppose the chancellor of the university drops a 2.00 kg water balloon from the administration building balcony 10.0 m above the ground. The chancellor takes the origin of his vertical axis to be even with the balcony. A student standing on the ground below the...

What is the effect of differing frames of references between entangled particles? For example, let's look at the below scenario: Photons are entangled in Alice's frame of reference on say earth. Photon B is put on Bob's spaceship that travels at say 95% the speed of light. The other photon A...

Hi guys, i need help for homework, it seems easy, but i can't do it:cry:, no calculation to do only writing 2D coordinates in different frames. Homework Statement The hallmark of an inertial frame is that any object which is subject to zero net force will travel in a straight line in a...

Homework Statement The problem, basically, is very simple but, it is confusing me. It says: "There is block on a moving train, which is being pushed by a man. The man applies force F to displace the block by s wrt Train. The moves S in that period. Find work done on the block by the force wrt...

I've read all sorts of descriptions in textbooks and online, but I don't get the purpose of reference frames. Why can't you just put everything on the same set of coordinate planes? I don't see what difference it makes. There was an example with a car traveling alongside another car, and that to...

Homework Statement I am doing a problem involving a man dropping a ball from the top of a mast of a ship at t =0 a height h above the origin of a ship's coordinate system. In the sea's frame of reference, the ship is moving with velocity u\hat{i} . The origins of these two frames...

Homework Statement You are traveling in a car going at a constant speed of 100 km/hr down a long, straight highway. You pass another car going in the same direction which is traveling at a constant speed of 80 km/hr. As measured from your car’s reference frame this other car is traveling at...

Hi I have recently started GR and have found the mathematics to be quite easy (have encountered differential manifolds and tensor calculus in other subjects), but the physics is troubling me, allow me to elaborate. In special relativity, we have a very intuitive idea of how observations work...

Are Lorentz transformations only work between inertial frames? if so, is there a simple counter-example e.g. for them not to work?

Homework Statement An observer in frame S standing at the origin observes two flashes of colored light separated spatially by Δx = 2300 m. A blue flash occurs first, followed by a red flash 5 µs later. An observer in S ' moving along the x-axis at speed v relative to S also observes the...

1. The question states: "Two lights are placed along the x-axis at positions x1 = 3.00 m and x2 = 5.00 m. The lights flash at times t1 = 1.00 ns and t2 = 9.00 ns. An observer in a rest frame moving to the right sees the lights flash in the same location. Assume that the origins of the two rest...

hi every one :) i need a small help please ... we have tow frames and tow observers , let suppose there is a force on an object in one of the frames , so from Newton law: f=ma "a" depend on "x" distance which is not constant in the other frame , so why they assumed that it is constant...

Homework Statement Suzanne observes 2 light pulses to be emitted from the same location, but separated in time by 3μs. Mark sees the emission of the same two pulses separated in time by by 9μs. a) How fast is Mark moving relative to Suzanne? b) According to Mark, what is the separation in...

I'm a bit unsure about the last couple of bits of this question, and I'm hoping someone might be able to help. Homework Statement a) Let a reference frame with origin O & Cartesian axes (x, y, z) be fixed relative to the surface of the rotating Earth at co-latitude θ (i.e. 0≤θ≤∏, where θ...

Hi to all, I am a new one to this physics forum and i have a doubt regarding Inertial Reference frames. In an article of IRF, it is given as "There is no absolute inertial reference frame, meaning that there is no state of velocity which is special in the universe." Can anybody please...

Homework Statement I will attach a scanned pic of the problem, but it seems to be a basic frames problem. However, everything seems to have to many unknowns on it to solve. I feel like I'm missing something simple, but I can't seem to make any more progress. Homework Equations ƩM=0...

Homework Statement A space traveler takes off from Earth and moves at speed 0.99c toward star Vega, which is 26.00 ly distant. How much time will have elapsed by Earth clocks when the traveler reaches Vega? 2. The attempt at a solution I looked at the problem solution, which...

Homework Statement Take the case of elastic scattering (A+B -> A+B); if particle A carries energy EA', and scatters at an angle θ, in the CM (center of mass/momentum frame), what is its energy in the Breit* frame? Find the velocity of the Breit frame (magnitude and direction) relative to the...

Basically: I jump forwards, exerting an amount of energy enough to push me forward with some velocity. But in my reference frame, I exert the same force, except the entire universe moves backwards with that same velocity, where did that energy come from? I sort of know this has to do with...

i was looking at the lorentz dilation and contractions for SR. My books says they are \grave{l}=l\gamma and that \grave{t}=\frac{t}{\gamma} .what i don't understand is that the velocity in the unprimed system is then \frac{l}{t} but in the primed system its \frac{l\gamma^{2}}{t} which is not...

It is my understanding that the faster an object moves, the more energy is required to accelerate it. As an object approaches the speed of light, an infinite amount of energy is required to further accelerate it, which is why no object can travel faster than the speed of light. But movement is...