Frame Definition and 1000 Threads

People tell me that we cannot extend our inertial frame, as defined in special relativity, across the Universe because that would be in violation of general relativity. The problem is that general relativity says that space-time can be curved whereas a global inertial frame assumes flat...

Homework Statement Determine the reactions at rocker support A and pin support B.Homework Equations ƩF = 0 ƩM = 0 The Attempt at a Solution ƩFx = 0: -Asin(25) - (800lb) + Bx ƩFy = 0: Acos(25) - (500lb) + By I'm getting thrown off because of the rocker on an incline.

Hi there! I'm working on a couple of problems regarding simultaneity. For one I'm given events X_a = (ct,x,y,z) = (2,1,-3,2) and X_b = (6,3,-1,5) I want to find out if there's a frame of reference where the events are simultaneous. I find the change vector X_b - X_a = (Δct,Δx,Δy,Δz) =...

Hello, The three clocks A, B and C is at rest in S frame. The clocks unsimultaneously change its frame from S to S'. The frame change events is simultaneous in S' frame. Now, clocks is moving in S frame and at rest in S' frame. I am struggling with this. The events on A clock displayed by...

Homework Statement When the box is at the bottom of the incline it will have a velocity of vf The person is an inertial frame of reference with a velocity of vf When the person starts moving, the box is moving backwards with the velocity of vf. This means at the top of the hill the box has...

We know that we can't say whether we are at rest or uniformly moving if we're in a einstein cage..but if the same medium is accelerating/decelerating can we being inside(and can't see outside) claim abt state of cage..?I ve read that a non-inertial can be converted to inertial by incorporating a...

The question: Suppose two identical particles, each with mass m and kinetic energy T, collide head-on. What is the kinetic energy of one in the rest system of the other? The solution: Is given on pg 109 of Griffiths' Introduction to Elementary Particles. Griffiths writes down the total...

Hi there, I am confused about the relationship between coordinate systems and reference frame in GR. I understand the coordinate systems can be used to describe reference frames, for example, Local inertial frames in GR can be defined by Riemann Normal Coordinates. However, take the...

Homework Statement An unstable particle called the pion has a mean lifetime of 25ns in its own rest frame. A beam of of pions travels through the lab with a speed of 0.60c. a) what is the mean lifetime of the pions as measured in the lab frame? b) how far does a pion travel ( as measured...

The apparent path of an object is different for observers in different reference frames. A ball dropped from the top of the mast on a moving ship lands at the base of the mast. An observer on the ship sees the path as straight down while one on the dock sees the path as a diagonal. How many...

A charged particle is placed next to a current-carrying wire. The wire produces a magnetic field, but if the particle is at rest, the field exerts no force on it. However, in a different inertial reference frame moving at speed v parallel to the wire, the particle is seen to be in motion, and so...

I have just completed my class 10th. I was presently reading the class 11th H.C Verma physics textbook and here is what I confronted which seems to me as if I am unable to fathom : Now I can't understand that how come acceleration of book with respect to Earth isn't 0 ?! Please see bold part...

Suppose, a long object is at rest in S frame. There is A (On the long object) and B (Near the long object, on the ground) observer in the middle of the long object. There are two clocks located on both end of long object. We suppose, both A and B is at origin of S frame and clocks at some -x and...

Hi, This is partly inspired by the questions in the thread about normal forces on a cornering car but I thought I'd post here instead of mix that thread up with my question. So suppose we have a biker leaning into a corner. There are the normal force and the force of friction which act at the...

I have a Plot using Frame, and AxesOrigin set to a convenient value. The plot process offsets the physical origin of the Frame so that the specified AxesOrigin is just inside the Frame border - ie there is an offset introduced for both axes. Is there a way to tell Mathematica not to set any...

Homework Statement A single story single bay building model has fixed fixed columns and a rigid beam. the total length of each aluminum column is 24 in. tall by 4 in wide and 32/1000 in thick. the plexiglas beams used for the base and top story are 12 in wide 4 in deep and .5 in thick. a...

If we have light, any particle, and maybe car, the particles travel at 0.98c and car let say 50m/s. Let them start moving at the same time to the given point let say 300 metres away. The difference between times of arrival of light and particle will be small compared to that between light and...

Is it possible to have a center of momentum frame in a system with a photon and a massive particle? If you were to do so in a system with two massive particles, this would involve redefining the velocity of the particles in the CM frame. E.g. if A moves towards B with speed 2v, in the CM...

Homework Statement -------------->Va Vb<--------------- FRAME REF A FRAME REF B -------------------------------------------- Stationary frame ref C An observer using the frame Ref A, calculate the length of ship B and the time it takes for the whole of ship B to pass by...

Homework Statement Two photons in the laboratory system have frequencies \nu_1 and \nu_2. The angle between the propagation directions is \theta. a) Write down the expressions for the total energy and momentum of the photons in the laboratory system. b) Find the photons’ frequency...

So, I need to make an Excel spreadsheet that realistically models the motion of a toy rocket. I need to take drag, gravity, and thrust into account, keeping in mind that the latter two will be influenced by the change in mass. The equation for force I must use, then, is: F = ma + v(dm/dt)...

Homework Statement A cylinder rotating uniformly about the x' axis of S' will seem twisted when observed instantaneously in S, where it not only rotates but also travels forward. If the angular speed of the cylinder in S' is ω, prove that in S the twist per unit length is yωv/c(squared)...

Hey guys, I am having some problems with the concept of inertial/non-inertial frames of reference and their applications in engineering dynamics. So I've learned that a given frame of reference is defined to be non-inertial when something in the studied system can only be explained through...

Ok, so I don't have much of an intuition for frame bundles, so I have some basic questions. A frame bundle over a manifold M is a principle bundle who's fibers are the sets of ordered bases for the vector fields on M right. 1) This means that any point in the fiber (say, over a point m in M)...

Hello, Suppose, A and B is clocks at both end of train. A is at left and B is at right. Observer O is at middle of train at point M. Observer R is on platform. Train is at rest and O synchronize both clock. The clock is synchronized with respect to both observer. Now, train starts moving to...

According to this, if someone spins around at 2 revs per second when the moon is in the horizon, the moon seems to move at 4 times the speed of light. And this implies the moon is not in our local reference frame. And per this, local inertial frame applies to "small regions of a gravitational...

Can one approximate an "ether" frame by analyzing "superimposed" rotating frames? If we assume the axiom that all motion is ultimately curved, however small the curvature, it would appear that for every momentum you are going to have a radial vector associated with the non-zero deflection of...

Would it be possible that every rest frame is going through a force field so everything will be smaller on atom level and time goes slower too (Lorentz, Einstein) ? So that force field is the holder of the encapsulated ration distance / time (C) ... That would explain the unknown time...

Homework Statement The electron is traveling at a speed of β=.9999999, γ=1957, with mass mc^2=.51099 MeV. The Proton is traveling at a speed of β=.9, γ=2.29, with mass mc^2=938.27 MeV. They are heading in opposite directions, directly towards each other on the x-axis Find the reference...

If you a mass being accelerated by a force which is acting upon a spring attached to the mass it will exhibit harmonic motion. However unlike a fixed harmonic oscillator there is no explicit solution to the equation which describes the motion of the mass in a reference frame outside of the...

Lets say for a moment that everything that travels at speed below c has a rest frame.. All kinds of waves are produced from entities which has a rest frame... for example, Water waves produced from water surface which has a rest frame, similarly sound waves from physical objects, light...

Hello, I've seen spin orbit coupling being explained by going to the rest frame of the electron and noting that the proton is then a moving charge and hence has a magnetic field, which interacts with the spin of the electron, effectively coupling the spin and angular momentum of the electron...

Homework Statement events A(ct,x)=(1m, 2m) and B(ct,x)=(3m,4m) are separated in a lightlike interval. I need to find the velocity of a separate reference frame in which they BOTH occur at the same time. Next I need to find the velocity of the frame where they will occur at the same...

So this is problem 11.1 out of Jackson Electrodynamics: Two equivalent intertial frames K and K' are such that K' moves in the positive x direction with speed v as seen from K. The spatial coordinate axes in K' are parallel to those in K and the two origins are coincident at times t=t'=0. (a)...

Do galaxies produce measurable/significant frame dragging effects by their rotation? I would think frame dragging depends on the mass and speed of rotation... Are such effects only felt at the boundary between rotating gravitational fields and flatter space, i.e. the edge of the milky way? Or...

Hello my name is Donald. I need some help analysing a frame for equilibrium at the joints. I will attach a drawing of the work I have performed so-far. I am stuck where the brace meets the right post at 2.5 ft. from top. This is my first try at posting, please forgive me for lack of knowledge...

As stated in SR, mass of the object increases with its velocity right? Lets assume that all the objects in the universe have consciousness and they all know what their rest mass is...(Leave photons out of the argument).. And also assume they all can measure their own mass at any instant...

I've just found out that in the centre of mass frame, the angle of deflection in a collision is different from in the lab frame. I vaguely understand why: if the frame you viewed the particles in was also moving but only horizontally it would make their horizontal movement appear to decrease...

Can someone give me a clue/hint to finish this question? "In a reference frame S, the electric and magnetic fields of an electromagnetic wave E and B are perpendicular to each other. Determine the velocity of a reference frame S' in which (a) E' = 0 and (b) B' = 0"

Hi. Ok, so I'm trying to understand the "navigation equations". n: frame traveling on Earth with vehicle. e: frame centered in earth, rotating with it. P: Position of vehicle center of gravity. v^{n}_{P/e} = (vn,ve,vd): velocity of P w.r.t to e-frame, expressed in n-frame. Normally...

A question please in three parts, need the numbers for the first before I can asked the next. A Machine lowers from rest, 100 pounds under control, at 2m/s, for 1000mm. Then immediately stops the weight, and lifts it back up at 2m/s. At the transition from negative to positive, what...

I found out that Proxima Centauri is 4.2 light years away from earth. If someone was on a voyage to this star via space ship, would this person measure the time to be shorter than 4.2 years if their spaceship was traveling 99.99999 percent the speed of light, assuming that the 4.2 years is...

Is this correct? There are two clocks on Earth that are synchronized. One clock goes out on a spaceship at .8c. Now according to the stationary or Earth FOR one year goes by for its clock but he sees that only .6 of a year has gone by on the clock of the spaceship. Now the spaceship...

So what will it see it self as?? At rest or moving a velocity c? Either way it seems to be a contradiction, so does that mean a photon can't be reference frame?

Last thread that I initiated was titled `Simultaneity is directional while Time Dilation is not', which presented a scenario for the Non-directional property of Time Dilation in STR. Which I think, needs to be reconsidered. And I believe this is the reason why `STR can only be worked out when we...

Homework Statement A particle moves in a rotating reference frame along the x-axis as x(t) = xo eat (xo and a are positive constants). The frame rotates with a time-dependant angular frequency ω(t) about the x-axis. The true physical force is in the x-direction of the rotating frame. Break up...

Hi there, I was doing some calculations with tensors and ran into a result which seems a bit odd to me. I hope someone can validate this or tell me where my mistake is. So I have a normal orthonormal frame field \{E_i\} in the neighbourhood of a point p in a Riemannian manifold (M,g), i.e...

Please excuse my ignorance - I am a biologist by training - but this is one of those questions that just keeps bothering me and I can't find the answer with Google/Wikipedia. Take as our example the ocean currents on the Earth caused by the Coriolis Effect of the Earth turning. When I read up...

I have been reading Einsteins Relativity and a simple concept in special relativity is tripping me up. I have heard that an object can never reach the speed of light. To which observer is this speed limit seen by. I know your answer will be "By all observers" but that is what I don't get...

Homework Statement B mesons can be created through the reaction chain e+e- → \Upsilon(4S) → B+B- by colliding beams of electrons and positrons head-on at centre-of-mass energy equivalent to the mass of the \Upsilon(4S) resonance. a) If the electron beam energy is 8GeV, show that a positron...