# Coefficient friction

1. Apr 21, 2010

### Sirsh

Hi. Im just wondering if I was going to attempt to find the coefficient friction of a book resting on a block off wood. How would I go about it?

http://yfrog.com/5gblockofwoodj

The horizontal distance is 15cm and the vertical distance is 6cm. Would i just do trigonometry to find the angle the book makes with the floor then substitute this into the equation tan$$\phi$$ = $$\mu$$?

Thanks! - sirsh

2. Apr 21, 2010

### joriarty

Is this an actual homework question, or just general curiousity? (if this is homework, have you told us all the information you were given? Doesn't look like it to me)

Either way, I think you need more information. I presume you want to know the coefficient of static friction, rather than kinetic. AFAIK a trig approach wouldn't work, I would have thought a physical experiment would need to be conducted.

Last edited by a moderator: May 4, 2017
3. Apr 21, 2010

### Sirsh

It's homework, i forgot to add that i have to push the book from the base until the book slipped and when i did the horizontal distance was 15.3cm nd the equation is coefficeint = N/F

4. Apr 21, 2010

### joriarty

I still don't know how to help here, sorry. You're either missing some information still, or I seriously need to revise my Newtonian mechanics :p

If you knew the mass of the book you could calculate the normal force, which would be a good start.

5. Apr 21, 2010

### Sirsh

i measured the mass of the book to be 0.109kg :)