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Homework Help: Linear Momentum

  1. Mar 4, 2009 #1
    1. The problem statement, all variables and given/known data

    A railroad car moves under a grain elevator at a constant speed of 4.50 m/s. Grain drops into the car at the rate of 680 kg/min. What is the magnitude of the force needed to keep the car moving at constant speed if friction is negligible?

    2. Relevant equations

    p = mv
    F = dp/dt

    3. The attempt at a solution

    ?
     
  2. jcsd
  3. Mar 4, 2009 #2

    LowlyPion

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    Homework Helper

    OK. So what is the Δmv?
     
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