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Homework Help: Fire by Friction

  1. Jan 2, 2008 #1
    How can one approximate the distance that one would have to move two sticks in order to start a fire at room temperature. With a given coefficient of friction and mass for the wood as well as the amount of force that someone can apply to the wood and the flashpoint of the wood.

    W = mc(flashpoint - room temp)
    (not sure what mass to use because heat will not spread out over the full mass of both sticks immediately...)

    Force of friction = Force applied x coefficient of friction -->
    W = Force applied x coefficient of friction x displacement

    Force applied x coefficient of friction x displacement = mc(flashpoint - room temp)

    So can I find displacement required like that?
  2. jcsd
  3. Jan 2, 2008 #2


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    You have the right idea. I would use total mass of the wood and assume the heat spreads through them immediately, even though it wouldn't. Sometimes, a scientist's best skill is being able to make simplifying assumptions.:smile:

    Anyway, I agree with how you are going about this. What do you get as an answer?
  4. Jan 2, 2008 #3
    Well if that sounds sane to someone else then I am going to try this for a paper on a topic of my choice, so I will get some of my data tomorrow (like masses and coefficient of kinetic friction by experimentation tomorrow and will look up specific heat and flash point and pick a convenient applied force) then I'll calculate a theoretical displacement and then try the experiment and see if its reasonably close, so I'll post some data then for verification.
  5. Jan 3, 2008 #4
    Never mind, I changed my topic...too many problems.
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