# Homework Help: Fire by Friction

1. Jan 2, 2008

### PPMC

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.

Attempt
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

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

So can I find displacement required like that?

2. Jan 2, 2008

### G01

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.

3. Jan 2, 2008

### PPMC

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.

4. Jan 3, 2008

### PPMC

Never mind, I changed my topic...too many problems.