What is Frames of reference: Definition and 110 Discussions

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?

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...

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...

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...

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...

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...

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...

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...

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...

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...

Post any thoughts or ideas here.

Homework Statement A frame is accelerating uniformly along the x-axis relative to an inertial frame (x,y,z) with acceleration a.Find the transformation between the frames given that the origins concide at t=0. Homework Equations The lorentz transformations cannot apply here ,but what...

Homework Statement A mass of 2 kg lies on a horizontal table that is placed in the back of a truck. The mass is held in position by a string and a force of 6 N acts on it in the -y direction. The truck then accelerates in the +x direction. As a result, an observer in the truck sees that the...

From what I can glean, since kinetic energy = 1/2 mv^2, it follows that a doubling of velocity requires a quadrupling of energy. One joule is required to accelerate a 1 kg mass from zero to one meter per second per second. ie 1m/s2. Now, to further accelerate the mass to 2 meters per second...

A swimmer who achieves a speed of 0.75 m/s in still water swims directly across a river 72 m wide. The swimmer lands on the far shore at a position 54 m downstream from the starting point. (a) Determine the speed of the river current. (b) Determine the swimmer?s velocity relative to the shore...

If all frames of reference are taken as equally valid. when a car moves, to the passengers in the car the world is moving in the opposite direction. Moving the whole world should take a lot more chemical energy than was contained in the gas that was burnt... I know the passengers in the car...

Homework Statement [PLAIN]http://www.antonine-education.co.uk/Physics%20A%20level/Options/Module_8/Topic_6/cars_4.gif What is the speed of sound, relative to: A - B - C - Homework Equations None. The Attempt at a Solution For B, since B is a stationary reference point...

Homework Statement If you are on the merry-go-round going in a circle at constant speed, are you looking at the world in an inertial, or non-inertial frame of reference? How do we tell whether from one's viewpoint, they are looking at something from an interial or non-inertial frame of reference?

Fairly straight forward question. If you have a set of three vectors specifying a frame of reference and a second set of 3 vectors stating another frame of reference. How do you get the Euler angles associated with that rotation? More generally I am considering the relative orientation of one...

Well I've just been learning about special relativity, and I think I understand everything I need to know, except frames of reference (for A level). I need to know where you are allowed to take frames of reference from, and where you are not. I understand that you can't take a frame of...

A very important idea in General Relativity is, same laws in all reference frames. How does that work in rotating reference frames? Jonny

I've had a good search through the archives and haven't found an answer to this question. Many apologies if this is old ground. . . Having read the threads on the Pioneer Anomaly a quick question to which I'm sure there is very simple answer (I just don't know what it is !): When...

Homework Statement the acceleration of a particle as seen from 2 frames s1 and s2 is 4 , what can be the value of acceleration between s1 and s2 Homework Equations The Attempt at a Solution the answer to this question is anything between 0 to 8 , but i do not know the reason , pl...

I accept that the FAQ section is there to cut down on repetitive questions, but this arises out of an answer in the FAQs. Would this line of reasoning not lead to the conclusion that, even without an inertial frame of its own, a photon would not be able to be stationary relative to itself?

This is what my teacher told me, but I still don't really see how it works. Say a person is in a car traveling at constant velocity, and it crashes into a tree, from an inertial frame of reference (the road), the person in the car continues traveling at the constant velocity of the car until...

Been reading up on physics out of pure interest, just learning really. Mainly started special relativity and learning about the inertial frames of reference. I think I understand that, but here's what I don't get. If from one inertial frame of reference moving at a constant 100 MPH, I toss...

Homework Statement You are standing on a slowly rotating merry-go-round, turning counterclockwise as viewed from above. You are holding a string from which is suspended a rubber stopper of mass 45g. You are 2.9m from the center of the merry-go-round. You take 4.1s to complete one revolution...

Hi, Second time I'm writing this question, the first one seems to have been lost in cyberspace but sorry if it somehow comes back and appears twice. Anyway, you know how kinetic energy depends on velocity, so that the energy of a particle collision will be different for two frames of...

Hello, I know that this is going to sound stupid, so please forgive me, but could someone give me a brief and simple definition of what an inertial frame of reference is and what a non-inertial frame of reference is? Thanks, Louis

Assume you have two objects, with nothing else, moving directly away from one another, each at 51% of the speed of light. But, from the frame of reference of one object, the other is going 102% of c, an impossibility. How does this work? And: Those same two objects, which has more energy...

I'm looking for a list of "natural" frames of reference on the cosmic scale. Something that can be used as "the" frame of reference for everyone in the universe that isn't arbitrary. So let's brainstorm about some potential candidates. The more the better. If need be, start with an idea and...

Homework Statement A child sits 2m from the centre of a merry-go-round (a rotating wooden platform) which is rotating at 3.5revs/min in a clockwise direction (when viewed from above). She places a wooden block of mass m=0.25kg beside her on the platform. a)Draw a diagram showing all the...

Consider an infinitely long straight conductor carrying a current. Let's assume that the free charges in the conductor are positive and are moving at a drift velocity v. Now, consider a particle of charge +q also moving with v in the same direction as the current at a distance r from the...

Hello, I am trying to understand the relationships of the time scales that obtain within different Inertial Frame of Reference. Not when viewing one frame from another, I am quite happy with the Lorentz factor for that. No it is how the local time scale, that measured by a stationary, local...

Hey! So, as I understand, kinetic energy of a moving object is proportional to its velocity squared. So I'm wondering where these inconsistencies come from, and how they are resolved: So, say two objects of mass M are travelling, with reference to a stationary observer, one in the left...

When an object is thrown by someone standing on top of a moving train, which variations of "frames of reference" would apply? (i.e. inertial, non-inertial, etc.) How would this principle work? (The object would go the same relative distance as it would if thrown from a person standing on...

Homework Statement A boat goes at 7.78 m/s [37 degrees west of south] in a current of 2.41 m/s [5 degrees north of west]. Find the velocity compared to the bottom. Homework Equations I think we use this: Vf2 = Vi2 + 2a x delta d The Attempt at a Solution I drew a diagram but...

Im trying to understand frames of reference, I am very new to relativity so sorry if I am being silly! Suppose you have a 2 spacecraft one traveling relative to the sun, and the other traveling relative to the first spacecraft in a perpendicualar direction. i know the velocitys of...

Homework Statement We have two frames of reference: K (x,y,t) and K' (x',y',t') such that initially x=x'=y=y'=t=t'=0. Now let K' move with a velocity \vec{v} = v [\tfrac{1}{\sqrt{2}},\tfrac{1}{\sqrt{2}}] Write Lorentz transformations in such a case. Homework Equations The Attempt at...

I keep hearing how motion only exists relative to something else. But what if there is some object in space, and it is the only object in the universe. It has some kind of propulsion system, and it activates it, goes to a certain speed, then stops accelerating. Is that object really moving, or...

Hello, I've come up with a simple, imaginary situation that bugs me. Could someone help resolve my confusion? Let's say that a spaceship is traveling through space, and two people- observer 1 and observer 2- are watching it. Both observers can monitor the ship's speed and the amount of fuel in...

I'm not going lie I don't know too much about relativity, though I do understand it. I haven't even gone to college yet and from what I've read so far I'm assuming there's much more to know. Anyway, in most of Einsteins thought experiments he speaks about observations in terms of 1 frame of...

hey :) So, I'm trying to switch between from one frame of reference to another, for a rotation of a 3d object. First of all, the object is rotated, through 2 perpendicular axis. Now, I need to model that rotation in another set of predefined Euler rotations. In other words, imagine a...

Homework Statement A smooth level table is centered on a platform which rotates. - The uniform rotation is at: one revolution in 12 seconds - Two perpendicular lines are drawn through the centre of the table, intersecting a circle of 1.20m radius at points: A', C', B' & D'. - Two men, H'...

Homework Statement here: http://img144.imageshack.us/img144/7518/26700576ok1.gif Homework Equations The Attempt at a Solution well, I tried to solve the motion equation from the inside table. I think there should be a d'elambertian force to the left, and friction force to the...

In the link: that I found here 5 minutes ago ( thanks for the link ) there are two drawings: the first and the second. In the first the link explains that there is a magnetic field, because the - charges are moving. In the second the link explains that there is not a magnetic field...

In an anniversary celebration of Marilyn Bell's 1954 crossing of Lake Ontario a swimmer set out from the shores of New York and maintained a velocity of 4m/s [N]. As the swimmer approached the Ontario shore, she encountered a cross current of 2m/s [E 25deg S]. Find her velocity with respect to...

Homework Statement A rubber stopper of mass 25g is suspended by string from a handrail of a subway car traveling directly eastward. As the subway train nears a station, it begins to slow down, causing the stopper and string to hang at an angle of 13 degrees from the vertical. What is the...

so here r ma doubts => it is sometimes heard tat inertial frame of referance is only an ideal concept and no such inertial frame exists.comment. =>the accelaration of a particle is zero as measured from an inertial frame of referance . can we conclude tat no force acts on it? => a...

Suppose event A causes event B. To one observer, event A comes before event B. Is it possible that in another frame of reference event B could come before event A? If so, how?