Reference Definition and 1000 Threads

Homework Statement A spacecraft is in circular orbit around the earth. with respect to a point below it on earth, it is traveling towards the east with speed v. Specify the reference state for potential energy. Homework Equations The Attempt at a Solution the total...

Please suggest a good book which deals with the whole mathematical description of relativity (special theory as well as general theory, with tensor analysis). Also it would be much appreciated if the description was not very concise, as i am not an expert in the subject. Much Appreciated. :)

I have no background in relativity. Recently I started reading some introduction to special relativity in Griffith's EM book, where he vaguely defined an inertial reference frame as one in which Newton's first law holds. Now according to this definition, does such frame exist in nature? On...

Just saw this paper discussed (sort of) on Reddit, and wondered if it is old news. http://www.reddit.com/r/Physics/comments/tgvpn/a_rederivation_of_special_relativity_from_chaos/ (the URL is truncated so it gives the wrong impression ;)) I can't understand the maths behind it, but am very...

I would like to read more about this version of simplicial homology and cohomology. Any reference or explanation is welcome. I hope this description is correct. Triangulate a smooth manifold and assign an orientation to each simplex in the triangulation. Define the boundary operator...

Need help understanding inertial frames of reference! I'm doing an A2 physics unit on special relativity (AQA) and am really confused about this, but I only want to get the idea so don't go to deep please :) I understand that a frame of reference is an area which is fixed relative to...

Ok I'm really trying to understand inertial and non-inertial reference frames, my understanding is as follows: A rest observer on the earth, the observer will be stationary relative to the earth.. Now as I understand it an inertial reference frame is one of which 2 coordinate systems are both...

Homework Statement You are flying your personal rocketcraft at 0.9c from Star A toward Star B. The distance between the stars, in the stars' reference frame, is 1.0 ly. Both stars happen to explode simultaneously in your reference frame at the instant you are exactly halfway between them...

My question is not homework. I feel ashamed of having this doubts but I'm really stuck on this. The problem is I have a reference frame xyz and here I define the COM \vec x{_{cm}} of the system. Now I move the COM reference frame x'y'z': \vec{x'}=\vec{x}-\vec x{_{cm}} In this reference frame I...

Homework Statement Specify and explain whether the following is an inertial or non-inertial observer: An observer is placed on a rock between Andromeda and the Milky Way. Homework Equations N/a The Attempt at a Solution So here is my understanding, the observer would be situated...

Hi, Physics Forums! This is my first post here and I know just about zero physics, so I apologize in advance if the question is a little daft/naïve. Ok, so here's what I'm wondering: suppose you have a light source that produces EM waves in all directions at some frequency ν, and a camera set...

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) =...

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...

Hi, I have a couple of questions about velocities in inertial and rotating frames of reference, related by the following equation: \mathbf{v_i} \ \stackrel{\mathrm{def}}{=}\ \frac{d\mathbf{r}}{dt} = \left( \frac{d\mathbf{r}}{dt} \right)_{\mathrm{r}} + \boldsymbol\Omega \times...

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...

Last week I read this article in Science Daily about BOSS and its recent most accurate measurements of the universe to date. http://www.sciencedaily.com/releases/2012/03/120330081844.htm In describing the experiment to measuring the accelerating expansion of the universe...

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...

Homework Statement The distance from Planet X to a nearby star is 12 Light-Years (a light year is the distance light travels in 1 year as measured in the rest frame of Planet X). (A) How fast must a spaceship travel from Planet X to the star in order to reach the star in 7 years...

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...

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...

In voltage divider, how high must the resistance on Vout be so that voltage divider can be used according to convention? I'm looking for official references.. If anyone can help I'd appreciate it.

quantum optics is a reference to a "c-number" Hi In my lecture notes on quantum optics is a reference to a "c-number" electric field, and it is stated that, since it is a c-number, there is no corresponding Hamiltonian. As far as I have understood, a c-number is a classical value of some...

Hello All, The following may be a simple problem. But, your thoughts will be very much appreciated. Homework Statement Let's use a gun with mass m1 and a bullet m2. The bullet is fired in the positive direction with speed v2, and the gun recoils in the negative direction with speed v1...

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...

Hi, Anybody used TI's SN74LV132 'NAND Gate with schmitt trigger i/p' in their design or any other similar part ? If so, please send me any Reference schematics or application notes.

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...

Homework Statement A 20g ball of clay is shot to the right at 12m/s toward a 40g ball of clay at rest. The two balls of clay collide and stick together. Call this reference frame S. Homework Equations What is the velocity of a reference frame S' in which the total momentum is zero...

This thought experiment involves two people named Person-A and Person-B. Person-A fires a gun from a car which is traveling at 60mph. Imagine that the bullet travels at a constant speed of 300mph for some time, assuming that the air friction is ignored. Person-B is stationary observing the...

Hello, I am having difficulty understanding the concept of Newton's first law only applying in an inertial reference frame, or a frame that is at constant velocity, however, apparently the 1st law no longer applies if the reference frame is accelerating. Can anyone give me some sort of concrete...

is the question

Hi, I'm looking for a QM mechanics book, which I could use for review and reference. I've took 3 QM courses, the first two was based on Cohen-tannoudji and Sakurai, and the third was about atoms and molecules etc. , although I haven't studied scattering theory and relativistic QM/QFT. (I took...

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...

How to choose an adequate reference electrode and what is the principal mechanism?

Hello. I am new to the idea of Special Relativity. From what I have read, based on what speed something is traveling it experiences an increase in mass. Let's say I am standing on the earth. I am experiencing a gravitational force of (me(m))/r^2. Now let's say I am the same person that somehow...

Homework Statement I a little lost on how to use the relativistic velocity addition formula to determine the increase in speed "v" over a short time interval in the Earths frame of reference, for a rocket having left Earth at rest and traveling through space accelerating at constant acc. of...

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...

The initial presentation of Newton’s Laws of Motion (NLM) to students often proceeds as follow: 1. The 3 laws are presented, 2. The caveat that the laws are only valid in Inertial Reference Frames (IRFs) is (sheepishly) mentioned, 3. An attempt is made to define an IRF, and 4. Some examples...

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...

As I understand in SR light is always c in it's local reference frame regardless of a present gravitational field. Light would appear to be traveling slightly less than c in a gravitational field otherwise known as the Sharpio Delay in all non-local reference frames. Now, light must be traveling...

reference in "the origin of species" I've been reading Darwin's "The Origin of Species". It turns out the benefit isn't so much seeing a familiar theory in original form, although there is a fascination in seeing evolution described without knowing Mendellian inheritance. The best benefit is...

Homework Statement Do objects same kinetic energy in all inertial reference frames? For objects interacting, is energy conserved in all inertial reference frames? Homework Equations None The Attempt at a Solution I think the answers are No for the first one, and Yes for the...

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"

Hello all :smile: I am trying to sort out how to use pass by reference properly and I am getting a Build error related to my pass by reference function. Perhaps someone could help me out here. I thought I was doing this correctly by reading my text, but apparently not. Maybe someone can...

I am re-posting this question here in a new thread as Humber mistakenly posted it in a two year old thread.

Is it possible for a particle to exist according to one reference frame and simultaneously not exist according to another? If energy is relative, can a collision between two particles have enough energy to produce new particles according to its own reference frame but not have said amount of...

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...

i came over the terms 'inertial' and 'non-inertial' frames during the study of rotational motion...pls clarify the difference...! plus can anyone give me a link from where i can practice numericals of angular momentum, moment of inertia, torque..

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?