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A relative problem

  • 19-04-2008 7:53pm
    #1
    IrishKnight
    Registered Users, Registered Users 2 Posts: 922 ✭✭✭


    Forgive the shamless title :P

    Can anyone gave a little help in relation to this problem...

    An absent-minded astronaut departs from earth travelling at 3/4c, forgetting to take his lunch. A second rocket is sent up but it only travels at 1/2c. In a desperate attempt to save the astronaut from starvation, his lunch is put on an escape capsule which is ejected from the rocket at 1/3c. Will the astronaut get his sandwiches according to Einstein ?


Comments

  • #2
    Spear
    Moderators, Computer Games Moderators, Technology & Internet Moderators, Help & Feedback Category Moderators Posts: 25,758 CMod ✭✭✭✭Spear


    IrishKnight wrote: »
    Will the astronaut get his sandwiches according to Einstein ?

    No, he's still travelling faster.


  • #3
    IrishKnight
    Registered Users, Registered Users 2 Posts: 922 ✭✭✭IrishKnight


    But why? According Newton he will get them, why then according to Einstein will he not get them?


  • #4
    Spear
    Moderators, Computer Games Moderators, Technology & Internet Moderators, Help & Feedback Category Moderators Posts: 25,758 CMod ✭✭✭✭Spear


    IrishKnight wrote: »
    But why? According Newton he will get them, why then according to Einstein will he not get them?

    Addition of velocities is done by the Lorentz transforms, not Newtonion linear addition.

    http://math.ucr.edu/home/baez/physics/Relativity/SR/velocity.html

    Hence the lunch ends up at .71c, slower than the astronaut at .75c.


  • #5
    M.T. Cranium
    Registered Users, Registered Users 2 Posts: 14,741 ✭✭✭✭M.T. Cranium


    He might get it, though, if he takes a wrong turn and the lunch goes straight through. Mine did. :eek:


  • #6
    SOL
    Registered Users, Registered Users 2 Posts: 1,155 ✭✭✭SOL


    But will the sandwich be fresher if they send it or if he came back to earth for it?


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