# Determining the coefficient of friction for various surfaces through lab experiment

1. Oct 14, 2009

### fishfish

1. The problem statement, all variables and given/known data

Hi, I'm new the PF and I was wondering if someone could help me with my lab.

This was the basic set up of our lab, with one mass being pulled by another mass up an incline. The ramp was placed on a desk while mass B was left to fall towards the ground. What we were supposed to do was dertermine the coefficient of friction of the material ( coloured red ) under mass A for each different run that we did with different materials. I don't really know where to start on this lab, other than finding the acceleration of the system, but what I'm really troubled with is having to find the force of friction on the incline...

For the first run...

mass of block A= 0.185 kg
mass of block B = 0.143 kg
dots on tickertape= 84 dots
time ( estimated from tickertape) = 1.4s

2. Relevant equations

∑F= Fgy _ Fgx(paralell)
= mygy + mxgsinθ

3. The attempt at a solution

∑F= mygy + mxgsinθ
= (0.143kg)(9.8m/s2) + (0.185kg)(-9.8sin16°)
= 0.9 m/s2

And then after this I don't know where to go...
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Oct 14, 2009

### tiny-tim

fishy welcome to pf!

hi fishfish! fishy welcome to pf!
(i assume you're intending to use F = ma to find the acceleration)

you haven't included the formula for the friction force, nor the total mass