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Heat Help

  1. Mar 12, 2009 #1
    1. The problem statement, all variables and given/known data


    A chain of metal links with total mass M = 6 kg is coiled up in a tight ball on a low-friction table. You pull on a link at one end of the chain with a constant force F = 69 N. Eventually the chain straightens out to its full length L = 1.0 m, and you keep pulling until you have pulled your end of the chain a total distance d = 3.6 m.

    before this question i have already answered these questions. might need the info to solve not sure though.

    (a) Consider the point particle system:
    What is the speed of the chain at this instant?
    8.4439 m/s


    Consider the real system:
    What is the change in energy of the chain?
    delta(E) = 248.4 joules


    3. The attempt at a solution
    i solved conservation of energy like
    Ef = Ei + W + Q
    then
    Ef = 248.4 + Q where Q = 0
    then
    final Ke + Ethermal = 248.4
    solved for Ethermal = 248.4 / Ke or 248.4/(1/2mv^2) using v found above
    i get 1.1613 J but that is wrong. where did i mess up??
     
    Last edited: Mar 12, 2009
  2. jcsd
  3. Mar 12, 2009 #2
    solved for Ethermal = 248.4 / Ke or 248.4/(1/2mv^2) using v found above
    i get 1.1613 J but that is wrong. where did i mess up??

    Instead of dividing by Ke....You have to subtract by Ke.
     
  4. Mar 12, 2009 #3
    haha i need to go back to basic math.
    thanks sriceb01
    and welcome to the forums.
    this site is great!!!
     
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