# What is the coefficient of friction between surface and the mass?

1. Feb 23, 2010

### yss83

1. The problem statement, all variables and given/known data
A mass of 50 kg is kept in uniform motion along a horizontal surface by a horizontal force of 4.08x10^6 dynes. What is the coefficient of friction between surface and the mass?

2. Relevant equations
(I searched previous answered questions and found this)
Ff= u * mg

3. The attempt at a solution
Our teacher hasn't actually started with our friction topic yet, but she always makes us do these assignments beforehand so we come "prepared" to her lectures. But I have no idea how to start. So I tried this, but I think it's incorrect.

4.08 x 10 ^ 6 dyn / (50 kg * 9.8 m/s^2) = 8326.531

Coefficients aren't supposed to be that big, right? So I tried converting. This is really embarrassing, but I'm not familiar with dyn so I had to look for its conversion factor to meters.

40.8 m / (50000 g * 9.8 m/s^2) = 8.32 x 10 ^-5

Even just clearing out the dyn thing would be great. I mean, if the values I used are correct? :) Thanks.

2. Feb 23, 2010

### rl.bhat

Hi yss83, welcome to PF.
Convert dyne to newton.
Keep mass in kg, and g in m/s^2.
Now find u.