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Homework Help: Did I do this right?

  1. May 28, 2007 #1
    Did I do this right??

    How much chemical energy would be consumed to travel 100km?
    * Assuming 100% efficency *
    Mass of car = 1953 kg
    velocity = 22.2m/s

    Here is what I did
    E = 1/2 m v^2
    E = 1/2 * 1953 * 22.2^2
    E = 481258.26 J

    Now I plugged the Energy I got into this formula
    W = F * D
    481258.26 = f * 100,000
    Divide both sides by 100,000
    F = 4.8 N

    Ok so thats the work that I have done. I don't think I was supposed to find the force. What is chemical energy. I thought I did it wrong becasue I thought I was supposed to use E = 1/2mv^2 and add the answer to the W =Fd answer.
    So Im kinda lost... Any help is appreciated!!
  2. jcsd
  3. May 28, 2007 #2
    Are you traveling on gravel/asphalt/sand/water? Are you repeating the question exactly as it appears in the assignment? It doesn't make sense.
    Last edited: May 28, 2007
  4. May 28, 2007 #3
    Asphalt, The assignment was to get the car up to 80km/h then shift it into neutral and see how far you coast.

    here is someother info you might need
    mu = 0.0251
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