# Finding the Coefficient of friction on an incline plane

1. Oct 11, 2011

### Trent Horn

I need to find the coeffcient of friction on an incline plane. I need the equation to find the coefficient for any givien angle. It part of a lab where I'm required to create the procedure and am stuck with how to create the equation. We can use a protractor or trigonomic functions to find the angle and the mass of the object can be found with a scale.

2. Oct 11, 2011

### dacruick

Show me the equation for the coefficient if you don't have an incline?

3. Oct 11, 2011

### WatermelonPig

Well, mu = tan(theta) is sometimes used. Depends though.

4. Oct 11, 2011

### Trent Horn

thanks watermelon that was the equation i couldnt get too that equation because i didnt have the trig functions to get there.

5. Oct 11, 2011

### dacruick

Maybe I don't understand what is going on, but it seems to me that mu = tan (theta) is just plain wrong.

6. Oct 13, 2011

### WatermelonPig

Assuming the only forces acting on the mass are gravity, the normal force, and friction, then it is true. SumF = mgsin(theta) - mu*mgcos(theta) = 0.