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Got wrong from right equations

  1. Dec 4, 2006 #1
    I got this problem while I was combining relativistic equations:

    For particle which is in motion,
    v = l /t
    or, l = v * t
    or, l= v * t0/(1-v^2/c^2)^(1/2) ' Relativistic equation for time "t"

    If the particle was light,

    l =(c * t0)/(1-v^2/c^2)^(1/2) ' Because velocity of light is always c; c*t0 is equal to l0

    or l = l0 / (1-v^2/c^2)^(1/2)

    But, the actual relation is l = l0 * (1-v^2/c^2)^(1/2)

    I must have been wrong somewhere. Where?
  2. jcsd
  3. Dec 5, 2006 #2


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    You should have been consistent when plugging v--->c in your equations.

  4. Dec 5, 2006 #3
    use lorentz-einstein transformation

    Your light signal that starts at t=0 from x=0 generates the event after a time t of propagation (x=ct;t=x/c) in I. The same event detected from I' is (x'=ct';t'=x'/c) and so
    with b=V/c.
    the best things a physicist can offer to another one are information and constructive criticism
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