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Confusing problem? HELP please

  1. Dec 29, 2007 #1
    Confusing problem? HELP please!!

    i am trying to solve this problem:

    In the 1950s, an experimental train that had a mass of 2.60 X 10^4 kg was powered across a level track by a jet engine that produced a thrust of 5.25 X 10^5 N for a distance of 509 m. Assume that air resistance is negligible.

    i am trying to find out the change in kinetic energy of the train and the final kinetic energy. however i cannot figure out what the velocity of the train is. Can anyone help please or provided an equation??


    Thank you
     
  2. jcsd
  3. Dec 29, 2007 #2

    arildno

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    You don't need it.
    You are to find the CHANGE in the kinetic energy; that can be calculated by the work done by the force given.
     
  4. Dec 29, 2007 #3
    im not understanding.. so find the change in work???
     
  5. Dec 29, 2007 #4
    Speed equation?

    how would i find the speed of the train in this problem:

    In the 1950s, an experimental train that had a mass of 2.60 104 kg was powered across a level track by a jet engine that produced a thrust of 5.25 105 N for a distance of 509 m. Assume that air resistance is negligible.

    The equation is d/t but i do not know what the time is. can anyone help please????

    [Edit: Multiple threads merged. One thread per problem please! - Doc Al]
     
    Last edited by a moderator: Dec 29, 2007
  6. Dec 29, 2007 #5

    Astronuc

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  7. Dec 29, 2007 #6
    If I assume the acceleration to be uniform, I would suggest to use the kinematic equation :
    [itex]V_{f}^{2}=V_{i}^{2}+2*a*d[/itex]

    as you know d and a.
     
  8. Dec 29, 2007 #7

    arildno

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    No, force times distance equals change in kinetic energy.
     
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