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Homework Help: Opent top freight train with coal

  1. Oct 10, 2008 #1
    Question 3 text A freight car moves along a frictionless level railroad track at constant speed. The car is open on top. A large load of coal is suddenly dumped into the car. What happens to the velocity of the car?
    Question 3 answers
    It increases.
    It remains the same.
    It decreases. <-----
    cannot be determined from the information given
  2. jcsd
  3. Oct 10, 2008 #2
    Looks good to me. Use conservation of momentum to confirm.

    [tex] m_1v_1 = m_2v_2 [/tex]

    m2 is greater than m1 therefore v has to decrease.
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