How Do Galilean Transformations Affect Measurements in Different Frames?

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Homework Help Overview

The discussion revolves around the application of Galilean transformations to analyze measurements in different reference frames, specifically involving a train moving at a constant speed and the timing of an event (turning on headlights) relative to two frames: the train frame and the track frame.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants explore the positions of the train's rear and front in both frames, questioning the implications of the train's length and the timing of events. There are attempts to calculate the coordinates of events and clarify the relative speed of the train in its own frame.

Discussion Status

The discussion is active, with participants sharing calculations and questioning the correctness of their interpretations. Some participants agree on specific calculations while others seek clarification on the setup and assumptions regarding the positions of the train and the timing of events.

Contextual Notes

Participants are working under the constraints of a homework problem, which may limit the information available and the assumptions that can be made about the scenario. The original poster expresses uncertainty about the correctness of their solution due to the lack of a way to verify it.

austim14
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βI solved this problem but I do not know if it is correct becasue there is no way to check it:
Imagine that we define the rear end of a train 120 m long to long to define the origin X'=0 in the train frame and we define a certain track signal light to define the origin X=0 in the track frame. Imagine that the rear end of of the train passes this sign at t+t'=0 as the train moves in the +X direction at a constant speed of 25 m/s. 12 seconds later, the engineer turns on the train's heasdlight. A) Where does this event occur in the train frame? B) Where does this event occur in the track frame

Homework Equations



Use Galilean transformation equations for position. β is the contstant velocity.
t=t'
x'=X- β*t

The Attempt at a Solution


Here is my work: 25m/s*12s=300m
300m+120m= 420m
Train Frame 420m

420m=X-300m
X=720m
Track frame 720mIs this correct?
 
Last edited:
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Here is my work: 25m/s*12s=300m
300m+120m= 420m
Train Frame 420m
What is the speed of the train relative to the train (=in the train frame)?

I agree with the calculations of the second part if you fix the value from (A).
 
I think it's the 25 m/s
 
If the train is 120 M long, and the rear of the train is at x' =0, what is the x' coordinate of the front of the train? (presumably the engineer is situated in the front of the train). (Assume that you have a set of coordinates permanently laid out along the floor of the train from the rear of the train to the front of the train). The front of the train is always situated at this x' location.

Assume you also have a set of coordinates permanently laid out along the side of the track starting at the signal at x = 0. At time t = t' = 0, what are the x coordinates of the rear and the front of the train? During the 12 seconds, how far does the front of the train advance along the x coordinates at the side of the track? What is its x coordinate after these 12 seconds?
 

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