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Homework Help: Energy problem with inelastic collision

  1. Jun 11, 2010 #1
    1. The problem statement, all variables and given/known data
    A railroad car with a mass 2.50x10^4 kg moves at 4.00 m/s. It collides and connects to 3 more cars each with the same weight as the first, they're moving 2.00 m/s. After they connect the final velocity was 2.50 m/s. How much energy is transformed into internal energy in the collision?


    2. Relevant equations
    I was trying to use [tex]\Delta[/tex]E=[tex]\Delta[/tex]K+[tex]\Delta[/tex]U=-fkd. I wasn't sure if this was the right approach, and I think maybe I'm setting everything up wrong because I'm not coming up with the right answer.


    3. The attempt at a solution
     
  2. jcsd
  3. Jun 11, 2010 #2

    rock.freak667

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    Homework Helper

    The change in kinetic energy should give the work done which should be the same as the change in internal energy.
     
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