Frame Definition and 1000 Threads

Can anyone refer me to a discussion of applying the technique of changing reference frames to problem solving? Why it works, and what it means. I'm familiar with using it in some E&M problems, but I guess I don't really "get" it. For example a particle in an E&M field has m\vec{a} =...

As far as I understand, a spaceship going around rotating black hole should gain additional acceleration due to frame drag. Right? So, would there be max speed gain, like in gravity assist, or could you accelerate infinitely? Thanks.

Scenario: Alice is "sitting" on photon A Bob is "sitting" on photon B both are moving in same direction, their paths are parallel to each other. Per relativity the speed of light is constant So Alice will measure Bob's speed to be c and Bob will measure Alice's speed to be c yet they are...

we know that particle having rest mass cannot reach speed of light,c. but if we apply results of special relativity to a photon,then it seems that for a photon 1)there is no time and 2)length is contracted to zero. 1) so does that...

I'm working problem from the upper division classical mechanics course on MIT OCW. No solutions are available. This is form the first P-set, question 4. Homework Statement A particle moves in a two dimensional orbit defined by x = A(2αt-sin(αt)) y = A(1-cos(αt)) Find the tangential...

How do we mathematically define a inertial frame in GR? Is it only a basis in some tangentspace or does it have to be induced by a coordinatechart? :/

As I understand it, Einstein's dismissal of the "luminiferous aether" was based on his discovery that there is no universal frame of reference, i.e. that no frame of reference is privileged in relation to all other frames. My question is whether this principle can also be stated in the inverse...

Does the Universe have a "Frame Rate"? Surely, thinking about it, things can't just smoothly transpose from one location to another, there must be regular gaps, (far to quickly for us to notice) where it "jumps" from one point in space to another. I think this because it seems hard to imagine...

Why can we not CHOOSE a reference frame locally and treat everything inside of it as an inertial reference frame. For example in a classroom, the classroom is moving with the Earth and so is a ball rolling down the class. Because they are both equally moving due to the Earth's rotation, why...

I've been giving some thought to the new scientist article about the equivalence principle. What initially seems like a very simple issue is remarkably tantalising. (please note- I'm not a physicist so this may be quite stupid) This led me on a little to the question of gravity and direction...

Hi Why is it that if you hit an object fast it requires less force to break it than if you hit the object slow and applied pressure to it?

I know that you're going to probably say that a frame of reference doesn't make sense for light, but I've uploaded a discussion (warning: has profanity) from another website (reddit.com) and I'm curious to see if the user Imhtpsnvsbl makes a valid point.

First of all I'm not sure if this is the right forum for this problem. Homework Statement Given that \overline{F}=m\overline{a} is valid in the lab frame S, show that: (a) it is also valid in a moving frame S' with a constant velocity relative to S, but (b) invalid in a moving frame with...

Hi. I was recently calculating some centroids and I was wondering if the point were I choose my origin affects the centroid position. I.e., if I choose my origin at a massive particle, will the centroid be the same as with any other reference frame? Thansk :)

This paper by Cacioppo and Gangopadhyaya deals with two variations on the Pole and Barn paradox. Both paradoxes are successfully resolved. However, with regard to the first paradox, an electromagnetic wave comes into being in one frame, but not in the other. I consider this to be a paradox in...

Due to my job and other classes, I've been studying ahead of my class by myself to not fall behind and I'm not sure if I'm oversimplifying this in my head and not really grasping the idea. Newton's First Law of Motion states that an object with a net force of zero stays in constant motion (or...

hi guys, i have a basic question on special relativity.. if the inertial reference frame denotes the frames that holds up the Newtonian 1st law, then can Earth be an inertial frame? i mean it changes direction of velocity as it moves in the orbit around sun, so its not in constant velocity ...

Homework Statement A pion in its rest frame decays into a muon and a neutrino. Find the velocity of the muon and its mean-lifetime in the pion rest frame. (I've done this part). The muon decays into an electron and two neutrinos. If the two neutrinos happen to travel in the same direction...

This is to understand about the mathematics and possible limitations of the concept of preferred frames in BM and why entanglement couldn't use one. Supposed you have a cruise missile sent out from Earth to a distant planet traveling at 0.99999 the speed of light. 30 Seconds after sending it...

hello, in relativity something can go faster than the speed of light as long as it is not in the observer's frame of reference which would say that a FOR has a size but i read that a FOR was infinite in all directions. Someone explain this contradiction please!

I know that the rest frame of the photon is a non inertial reference frame. In that sense obviously the physics will not be Lorentz co-variant and so on. I have the following question Is possible to define a coordinate transformation from an inertial reference frame to the rest frame of a...

came across the concept of Frame dragging. i cannot find if this phenomena also aids in addition to the conversation of angular momentum the formation of an accretion disk around neutron stars/black holes. cheers

We have a problem of perfect reference frames( according what we are taught in school) If universe is expanding, the so called fixed stars are also moving. According to the special relativity, the speed of light is constant in every reference frame, So if we let light as the perfect reference...

Homework Statement Homework Equations Frotating = Finertial + Fcor + Fcf The Attempt at a Solution For the inertial field: F = -qv x b -kQq/r2 For the rotating field it would be the same term plus the coriolis and centrifugal forces. The issue I'm having trouble with is this: The v...

hi can inertial reference frame be in different sizes at least in theory? i mean that can there be two different frames of reference in same place at same time, where the observer in both frames observes physical laws to be normal in their own frame of reference, but the other frame appears to...

Homework Statement consider a pion decaying into 2 photons. In the rest frame of the pion, the two photons must emerge back-to-back photons are equally likely to emerge in any direction. determine the rest frame angular distribution of the emerging photons. Homework Equations ΔP=f(θ)Δθ is...

Hi, Homework Statement A square frame with a thin crust/layer of liquid with surface tension γ is given. Into the plane of the frame an elastic wire of circular shape with radius r_0 is inserted. The thin crust/layer of liquid is then burst (by pricking) and as a result of the force of...

Imagine a stationary charge q located on the positive y-axis at a distance r from a stationary observer at the origin. Let us assume that the distance r is large enough such that the electrostatic field due to the charge is negligible at the origin. Now let us assume that the charge q is given...

Hi! I think this should be a fairly easy question to resolve, but it's currently giving me fits... Suppose we consider a system of three interacting particles where we assume two of the particle (at positions r1 and r2) have infinite mass (such that we can ignore their kinetic energy) and do...

hi, last week we did an experiment to find the deflection of simply supported beams. During the experiment, after every measurement we had to tap the frame slightly. Does anyone know why we had to do this? If you could explain it to me I would be grateful.

Homework Statement calculate the frenet frame for the vector: \vec{r}(t)=(2t cost,2tsint,5t) calculate the acceleration in frenet frame. Homework Equations \hat{T}=\frac{dr}{ds}=\frac{\dot{r}}{|\dot{r}|} \hat{N}=\frac{\frac{dT}{ds}}{|\frac{dT}{ds}|} \hat{B}=\hat{T}\times \hat{N}The Attempt...

Homework Statement In a given reference frame, event 1 occurs at t1 = 0 s and position x1 = 0 m while event 2 occurs at t2 = 3.6 × 10^−4 s and x2 = 0.60 × 10^5m. Is there a second reference frame in which these events could be at the same place but different times? If so, specify its motion...

Recently learned about Special Relativity, so my brain is running perpetual circles around itself asking questions. So, I figured I would come here and ask where could I find out more information about the Lorentz Factor being undefined at a luminal velocity? Or more basically, where do I...

I saw this video of BMW car manufacturing plant on YouTube, and they showed how the robots fix metal sheets of various shapes onto the main frame ("skeleton") of the car. I was wondering: How to they make those metals in those particular shape. On one side there is the frame work, and the...

Hi, I am having some difficulty doing the integral ∫d^{3}v1d^{3}v2 | \overline{v1}-\overline{v2}|, where u1\leq|v1|,|v2|\lequ2, and \overline{v1} means vectors. It seems better to evaluate it in the center of mass frame, by substitution \overline{v1}+\overline{v2}=\overline{V}, and...

Homework Statement Show that the quantity T = c^2(Δt)^2 - (Δx)^2 - (Δy)^2 - (Δz)^2 is invariant under a change of frame Homework Equations Lorentz transformations Δx' = \gamma(Δx - vΔt) Δt' = \gamma(Δt - vΔx/c^2) Δy' = Δy Δz' = Δz The Attempt at a Solution I know that the way to do...

Let $$M$$ be a surface with Riemannian metric $$g$$. Recall that an orthonormal framing of $$M$$ is an ordered pair of vector fields $$(E_1,E_2)$$ such that $$g(E_i,E_j)=\delta_{ij}$$. Prove that an orthonormal framing exists iff $$M$$ is orientable and $$M$$ admits a nowhere vanishing vector...

Is frame dragging in GR the same as torsion in curved spacetime?

Before I say anything, I don't really have any experience in physics. But this question just popped into my mind concerning cause and effect and I can't seem to find the answer to it on the web. Here it is...Are cause and effect the same thing if a frame of reference is not present? For...

Hi, I am interested in the issue of frame dragging used in a number of galactic rotation models. However, I wanted to first make sure that I have a better understanding the relativistic implications of frame dragging. While the issue of galactic rotation is not the subject of this thread, it is...

Homework Statement For the frame shown (see attached picture) , work out the horizontal reaction at B (ie find Bx)Homework Equations EQUILIBRIUM EQUATIONS: sum of moment = 0 (CCW is positive) sum of vertical forces = 0 (up is positive) sum of horizontal forces...

I am working on an SAE Baja vehicle for a competition as part of my coursework requirements. Right now I am trying to come up with a method to estimate the forces that the frame will be subjected to. I need help doing this. I know that the top speed will be 30mph and that the vehicle will weigh...

This is a conceptual problem which I am facing for many days. If we convert a scenario in an inertial frame into a rotating frame, we apply a pseudo force i.e. centrifugal force radially outwards on the particle. Right? Also if a particle is having a circular motion in any frame of...

Let's say something is moving very fast past you. You see the thing to be length contracted. But let's say that thing suddenly slows down very fast and enters your inertial reference frame. Will it suddenly appear to you to have lengthened? My tutor said that this is not the case because of...

Homework Statement If you are in a noninertial reference frame, that means: Homework Equations The Attempt at a Solution I know that nonintertial reference frame is something that is moving. However, if I am in it, then should I be moving together with it?

Homework Statement A particle leaves its initial position Xo at time t=0, moving in the positive x direction with speed Vo but undergoing acceleration a in the negative x-direction. Find expression for (a) the time when it returns to Xo and (b) its speed when it passes that point I'm...

Hi, I just finished class and my professor was writing some of Newton's Laws on the board and derived some equations. We ended up with: V(Δt)=FΔt (this is for velocity in first inertial frame V(2Δt)=2FΔt (this is for velocity in second inertial frame Then he went and got the position in...

Hi the following question is from a previous exam for the subject Design of concrete structures, just wondering if I can get any pointers as I was not able to find the reactions.

Homework Statement Find a system K' in which the following events in frame K appear at the same time: i) x1 = a; t1 = (2a) / c; y1 = 0; z1 = 0 ii) x2 = 2a; t2 = (3a) / (2c); y2 = 0; z2 = 0 Describe the motion of K'. Homework Equations Lorentz transformations; time dilation...

Hello everyone. I have been trying to think of some practical and cheap airship designs. I have done some calculating, and if you were to have an airship's envelope in a cylindrical shape that is 300' long and 75' in diameter, it would be able to lift approximately around 45 tons if filled with...