Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Relative Velocities

  1. Jan 18, 2015 #1
    Lets suppose three objects O,A and B are set up in universe and nothing else.Then O seems A is moving 0.3c And B is moving 0.5c .In Special Relativity we have relative velocities formula I want to formule it but result seems absurd can you find me all possible velocities I mean A, O and B observer
    Thank you
     
  2. jcsd
  3. Jan 18, 2015 #2

    Doc Al

    User Avatar

    Staff: Mentor

    What results did you get? Why do they seem absurd?
     
  4. Jan 18, 2015 #3
    VCB=VOB-VOC I thought like this But this is not true in special relativity.In special Relativity it like the relative formule for special relativity isnt it ?
     
    Last edited: Jan 18, 2015
  5. Jan 18, 2015 #4

    Doc Al

    User Avatar

    Staff: Mentor

    You'll need to define your terms. (What is C, for example?)

    You'll certainly need to add the velocities using special relativity, not Galilean relativity.
     
  6. Jan 18, 2015 #5
    C is speed to O
     
  7. Jan 18, 2015 #6

    DrGreg

    User Avatar
    Science Advisor
    Gold Member

    But you said there were only 3 objects O, A and B, so there is no object C? I'm going to assume by "C" you mean "A", so, in Newtonian theory it would be[tex]
    v_{AB} = v_{OB} - v_{OA}.
    [/tex]Then in special relativity it is[tex]
    v_{AB} = \frac{ v_{OB} - v_{OA} } { 1 - \frac{ v_{OB} v_{OA} } {c^2} },
    [/tex](provided all velocities are parallel).
     
  8. Jan 18, 2015 #7
    Thanks
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Relative Velocities
  1. Relativity of velocity (Replies: 1)

  2. Relative velocity (Replies: 2)

  3. Relative velocity (Replies: 4)

  4. Relative velocity (Replies: 53)

Loading...