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Basic Special Relativity

  • #1
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Homework Statement


A star is 27c*y away from the rest reference of earth. A rocket reaches star A from earth and according to clocks on it 12 hours have passed. How fast is the rocket traveling in earth's reference frame?


Homework Equations


tpγ=t
Lp/γ=L


The Attempt at a Solution


The problem is under the category of length contraction and time dilation so I assume these are the two equations I must use. However when trying to do the problem I only was given t and Lp, and yet there are three variables (tp, L, and v). Help ;-(
 

Answers and Replies

  • #2
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Can you calculate what time has passed wrt IRearth?
(I am assuming Earth is assumed to be an IR and the ship doesn't accelerate.)
 
  • #3
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yes, no acceleration.
I don't think I can calculate the time wrt IRearth..? I would need to know the velocity to do that so I knew the gamma factor correct?
 
  • #4
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vearth=dearth/tearth
tearth=dearth/vearth
plug and chug.
 
  • #5
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I don't know t_earth though? I only know it took 12 years from the spaceships frame..? oh... is Vearth 27c*y / 12 years...? i'm a noob X_X
 
  • #6
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but that's not REALLY the speed earth see's it moving is it? Because earth couldn't see the rocket traveling faster than C could it?
 
  • #7
662
307
vearth=dearth/tearth
tearth=dearth/vearth
plug and chug.
tearthγ=t
or, tearth=t/γ
equate the tearth
Quadratic eq in v2*earth
*editted
 
Last edited:

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