Frames Definition and 631 Threads

Homework Statement There is a planet of mass m_1 orbiting a star of mass m_2. One question is "What is the semimajor axis of the planet's orbit in the coordinate system centered at the star's center", and another is "What is the semimajor axis of the planet's orbit centered at the center of...

Homework Statement Hi, My question probably has a simple answer, but I've been scratching my head over it a little too long so I thought I would ask it here. I have three initial photons involved in a collision with 4-momenta k1, k2 and k3. I have two reference frames: frame 1: the...

Hi, My question probably has a simple answer, but I've been scratching my head over it a little too long so I thought I would ask it here. I have three initial photons involved in a collision with 4-momenta k1, k2 and k3. I have two reference frames: frame 1: the centre of mass frame of...

1. The Question Verbatim "A pilot starting from Athens, New York, wishes to fly to Sparta, New York, which is 320 km from Athens in the direction 20.0 N of E (LETS CALL THIS VECTOR = A). The pilot heads directly for Sparta and flies at an airspeed of 160km/h. After flying 2.0 h, the pilot...

edit: this problem is about energy discrepancies when changing frames and is no homework. suppose I accelerate a car from 0 to 100. the energy difference is 1/2 m v^2 - 0 = 1/2 m 100^2 = 5000 m joules now I accelerate another car from 0 to 50. the energy difference is 1/2 m v^2 - 0 = 1250 m...

Homework Statement Two events happen at the same point x'(0) in frame S' at t(1)' and t(2)' a) Use equations x=gamma*(x'+vt') and t=gamma*(t'+vx'/c^2) to show in frame S the time interval between the events is greater than t(2)'-t(1)' by a factor of gamma Homework Equations The...

Homework Statement Consider a head-on, elastic collision between two bodies whose masses are m and M, with m << M. It is well known that if m has speed v0 and M is initially at rest, m will bounce straight back with its speed unchanged, while M will remain at rest (to an excellent...

This is the question: A physics lecture demonstration uses a small canon mounted on a cart that moves at constant velocity v across the floor. At what angle theta should the cannon point (measured from the horizontal floor of the cart) if the cannonball is to land back in the mouth of 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...

Hey all, I made a post earlier today on gravitational time dilation. It got me thinking that in any accelerated frame of reference there must also be a time dilation, due to the equivalence principle. This can simply be a elevator accelerating through space or it can be caused by centripetal...

Do accelerated observers also see the same constant speed of light as inertial observers? How do we transform to an accelerated frame? For simplicity, I mean a constant acceleration, constant in direction and magnitude. By acceleration I mean the second derivative with respect to lab time...

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...

I enjoy a good space opera and have always wanted to write my own, but at the heart of most space operas, even the relatively “hard” sci-fi ones, lurks the FTL drive. Plots just don’t advance well without them. But if relativity is correct, then FTL is the same thing as time travel, which leads...

Hello everybody ! This is my question: Suppose you have a mass m0 inside an ellipse (at rest). Suposse someone see it from another frame, from this frame he will see the ellipse contracted. I know there's no black hole, but, how can explain our observer this result? I'm trying to see only...

R' is an observer from I'. A rod is in a state of rest relative to him. He measures its proper length L(0). An observer R from I measures its Lorentz contracted length L related by L=L(0)sqrt(1-vv/cc) (1). If we reverse the situation, R measuring the proper length of the rod R' measuring its...

Some Inertial Frames may be more Equivalent than Others Silly proposition - but take the peculiar results predicted by Einstein in Part IV of the 1905 paper with a little extra added. We place two clocks at locations A and B separated by a great distance L. We identify A clock with an S'...

If paintings were not put in rectangular frames but in triangular or hexagonal or circular frames what difference would this make to the end product? Would the artist be forced to think differently?When the Romans came to the United Kingdom in the first century AD they brought the idea of right...

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?

is centripetal force present in inertial and non-inertial frames?

Does speed of light Change with respect to accelerating frames It shouldn't be as gravitational time dilation exists

OK, this is a spin off from another thread, but it's an interesting topic in its own right. What I'm going to try to do is to give a rather physical interpretation of accelerated frames, specifically the Rindler metric, and a physical (rather than mathematical) interpretation of the Rindler...

A train of length 15cs moves at speed 3c/5. How much time does it take to a pass a person standing on the ground? [That is, what time elapses on the person's watch between the time when he is next to the front of the train, and the time when he is next to the back of the train?] Solve this by...

My textbook basically defines an inertial reference frame as follows: If you have an object O that has no forces acting on it, and there is a reference frame R where the acceleration of O with respect to R is zero, then R is a inertial reference frame. This to me seems circular. How does one...

Not sure how to go about proving that if E and B are perpendicular in one Lorentz frame they are perpendicular in all Lorentz frames.

Hi - I've just started having lectures on special relativity at uni. We were talking about inertial reference frames and how these can be characterised by the facts that: 1) They move relative to one another with constant velocity, and 2) Newton's laws operate in inertial reference frames...

A flash of light is emitted at point O and is later reabsorbed at point P. In frame S, the line OP has a length l and makes an angle theta with the x axis. In a frame S' moving relative to S with a constant velocity v along the x axis: How much time tau' elapses between emission and absorption...

c) What is the relative velocity of the two reference frames?

:confused: I am in desperate need of help with a certian physice question I am struggling on. here's the question: "A pilot is required to fly directly from london to rome, in 3.5hours. the displacement is 1400km [S 43degrees E]. a wind is blowing with a velocity of 75km/h [E]...

"In Principle, worldlines allow us to relate events on one another - to do sciecne without using reference frames at all". This was in Wheeler and Taylor's Intro to SR book. My question is, isn't this false? Because worldlines exist in a spacetime diagram. Vertical being time and horizontal is...

I have a few questions here, and I'm stuck/confused on some of them. Here they are: 1. The air speed of a small plane is 215 km/h.The wind is blowing at 57 km/h from the west. Determine the velocity of the plane relative to the ground if the pilot keeps the plane aimed in the direction [34...

i hope u can answer these ? for me please 1) how does einstein's special theory of relativity and inertial frames of reference explain and predict the behaviour of natural phenomena (weather)? 2)explain the conservation mass -energy as applied in special relativity? 3) what is the...

Hi! When we measure the Kinetic energy, which is the correct frame of reference that we must choose? Thanks :smile:

Hi, I've run into a relativistic kinematics question that I'm not sure how to approach. The question states: "A source and a detector are spaced a certain angle \phi apart on the edge of a rotating disk. The source emits radiation at frequency \omega in it's instantaneous rest frame. What...

under which conditions we could say that the same experiment is performed in different inertial reference frames. I have formulated for myself the following answer: We say that observers from two inertial reference frames perform the same experiment if the physical quantities they measure are...

Hi, Please help me, I can't make head or tail of the concept of an inertial reference frame. What is an inertial reference frame? In what fundamental way does it differ from a noninertial reference frame if all motion is relative? Thanks for your help. Molu

Energy is not an invariant quantity between different frames of reference. For example a particle having a kinetic energy in one frame has a zero kinetic energy in another frame. But what about interaction energy? If I know the interaction energy between 2 particles in one frame, how can I...

What is used to define an inertial frame in special relativity? Do I need to take one of the postulates as defining an inertial frame? What is bothering me is that I used to use Newton\'s first law to define inertial frames (a freely moving object will have a constant velocity). This can...

Consider two farmes of reference moving relative each other. In one of the frames the CMD is fully isotropic, i.e., it looks the same in all directions. In the other frame however, the CMD should be red shifted in one direction and blue shifted in the other direction. Thus, the first frame can...

A first spaceship S1 departs from Earth and quickly accelerates to a velocity V = c/2. S1 travels the shortest path (dead heading) toward a distant planet Alpha so that it arrives in 20 years as measured by a clock on S1. One year after S1 is launched from Earth as measured by a clock on the...

Is the comparison of the kinetic energy of a satellite in orbit around the Earth to that of a truck traveling down a road realistic? Are they in the same reference frame?

hi, in the case of elastic collision of two balls in constant speeds, if we took the origin in the center of of one of the balls, so the speed of the origin ball will be always zero, and the second ball will has the speed of v befor the collision and -v after the collision. so how the...

If quasars are appearing to travel at almost the speed of light from us, what would the relative time frames between us be.

when I read what inertial frames I understand and it make sense but unfortunately when I try to apply what I understood on that question ,I can't illustrate these frames. Please help. question is that: I am standing on a level floor at the origine of an inertial frame ( S) and kick a...

I can't figure out the correct explanation for this gedanken. 1) We have a room in deep space which is shielded from external EM fields. The walls are lined with photon detectors. Inside is a charged ball attached to an insulating rod. The other end of the rod is on an axis and the rod is...

What is the difference in magnitude between the effects of normal doppler effect and doppler effect in accelerated frames, e.g. when the (light)source is accelerating wrt the observer? What is the formula for doppler effect in accelerating frames?

ok one of the postulates of special relativity is that the speed of light is constant in any intertial reference frame right? Has there been any experimental proof of this? When I learned this, my teacher mentioned the michalson-moray (spellings probly wrong) experiment that disproved the...

This is a highly theoretical question... so beware! The Work Energy(WE) equation in Mechanics says that the net total work done on an object due to various conservative and non-conservative forces equals the change in kinetic energy of the body. This above theorem is usually derived simply from...

Are you in inertial frames? hi, today my friend ask me 2 simple questions, too shame i cannot answer him...so i post it here: is the classroom an inertial system ?? Earth is rotating around the sun - so ...can still consider as inertial ? 2. If u working in laboratory to find so physics...