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Time needed for superman to stop the train

  1. Feb 6, 2010 #1
    can some one give me an outline of how to solve the following question?


    Superman (mass=84.0 kg) must fly into a train (mass = 18079 kg) traveling at 75.0 km/hr to stop it.
    Calculate the minimum time Superman must take to stop the train, if the passengers experience an average horizontal force of 0.420 their own weight.
  2. jcsd
  3. Feb 6, 2010 #2
    Re: collision

    If the train is stopped, the passengers have also stopped.
    Use F=ma on a passenger
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