Special relativity transformations

Click For Summary

Homework Help Overview

The problem involves special relativity transformations, specifically analyzing two light flashes occurring at different times and positions in a laboratory frame. The goal is to determine the speed of an inertial frame in which these events are simultaneous.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to apply Lorentz transformations to relate the time and position of the events in different frames. They express confusion regarding the outcome of their calculations, suspecting a potential misprint in the problem statement.

Discussion Status

Some participants have engaged in checking the assumptions made in the problem, with one suggesting the possibility of a misprint regarding the time units. Another participant confirms this suspicion based on the reasoning presented.

Contextual Notes

There is uncertainty regarding the accuracy of the problem statement, particularly whether the time should be in microseconds instead of milliseconds, which could affect the calculations and interpretations of the results.

zhillyz
Messages
64
Reaction score
0

Homework Statement



Two light flashes occur on the laboratory x axis, the first at time t=0 and
position x=450 m, the second at time t=+1 ms, at the origin. In an inertial
frame moving along the x-axis with speed v, the events are simultaneous.
What is the speed v?

Homework Equations



From the question I have decided that the relevant equations are the Lorentz transformations. We know the position's in the rest frame and we know the time of the events. In the moving frame we know the the events are simultaneous. So we can't use the transforms for x as there would be two unknowns [itex]\Delta x'[/itex]and [itex]v[/itex]

The Attempt at a Solution



[itex]t_{1}' = \gamma (t_{1} - \dfrac{vx_{1}}{c^2})[/itex]
[itex]t_{2}' = \gamma (t_{2} - \dfrac{vx_{2}}{c^2})[/itex]

[itex]t_{2-1}' = \gamma (t_{2} -t_{1} - \dfrac{v}{c^2}(x_{2} - x_{1}))[/itex]

[itex]0 = \gamma((1*10^-3) - 450\dfrac{v}{c^2})[/itex]

[itex]0 =(1*10^-3) \gamma - \gamma 450\dfrac{v}{c^2}[/itex]

[itex]\gamma 450\dfrac{v}{c^2} =(1*10^-3) \gamma[/itex]

[itex]450\dfrac{v}{c^2} = (1*10^-3)[/itex]

[itex]v = \dfrac{(1*10^-3)}{450} c^2 \mbox{WRONG!}[/itex]

Not sure what I am doing wrong. Any help on how to tackle these questions would be great.
 
Physics news on Phys.org
Unless question sheet is a misprint and it should be micro rather than milli(seconds)?
 
Your reasoning seems to be correct, and using the numbers given does give a non-physical result, so you are perhaps correct in thinking that there is a misprint in the question.
 
Thanks, my lecturer got back to me and confirmed this :). I appreciate you taking the time.
 

Similar threads

  • · Replies 11 ·
Replies
11
Views
1K
Replies
6
Views
2K
Replies
3
Views
1K
Replies
23
Views
2K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 12 ·
Replies
12
Views
1K
Replies
46
Views
7K
  • · Replies 12 ·
Replies
12
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
170
Views
9K