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Homework Help: Magnitude of total resistant force on a car?

  1. Nov 16, 2011 #1
    1. The problem statement, all variables and given/known data
    A car needs to generate 75 hp in order to maintain a constant velocity of 27.3m/s on a flat road. What is the magnitude of the total resistive force acting on the car. (due to friction,air resistance etc.)

    2. Relevant equations

    1hp=746 watts

    3. The attempt at a solution the answer is 2.05*10^3N but idk how to get it.
  2. jcsd
  3. Nov 16, 2011 #2

    Andrew Mason

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    In one second how much energy does the car use? So how much work does the car do against the resisitive force in that second? Over what distance is that work done in that second? What is the relationship between Work, Force and distance?

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