# Friction coefficient and forces

1. Sep 25, 2006

### rkslperez04

Hey there,

Can you someone explain the "mu" in friction?

I understand that Force=Mass*Acceleration but then it asks for coeffeiencent of friction??

F=ukFn ????

I see it says that F=mg but the friction equalls the constant of the "mu"...the examples in the book are sketchy and wording is over my head.

2. Sep 25, 2006

### laminar

U stands for mu_k in this post

u is the friction coefficient. The force of friction is found by multiplying u, which has no units, by mg.

F=umg

Then solve for u. If you know u you can find the force required to move an object across the surface.

F=uma

3. Sep 25, 2006

### RoyalewithCh33s3

If you want more, there is a decent wikipedia entry on the http://en.wikipedia.org/wiki/Friction_coefficient#Coefficient_of_friction" that you might want to check out.

Basically, the value "mu" is a constant (depending on the surfaces) that shows the ratio of the force of friction and the force normal, which is the same as the force pushing the object into the surface.

Here is another http://www.phy.ntnu.edu.tw/ntnujava/viewtopic.php?t=18" [Broken] with an explanation you might want to check out. Just play around with the coefficient and you will start to see the relationship between it and F.

Last edited by a moderator: May 2, 2017
4. Sep 25, 2006

### rkslperez04

GREAT ... the wikipedia was helpful...Im going to apply it to the problems I have...

and..

Thanks for pulley site.. we just an experiment like that in class!

>>>So.. When it says find frictional force..

I just mulipliy u by the force..

Friction="mu" times "force on object"

Im going to the learning lab on campus for extra help... thanks for filling in the gaps!