# Bracket/block static friction problem (physics)

1. Sep 23, 2009

### notbynumber

1. The problem statement, all variables and given/known data
http://img3.imageshack.us/img3/6618/5n6.jpg [Broken]
Image there.

2. Relevant equations
Well this is actually where the problem occurs. You make your own equations.

3. The attempt at a solution
It's the friction that is really messing me up. I'm just so confused, I'm going to show you my attempt at FBDs for the problem.

I think that if I just know how to draw them correctly I'll be able to find my answer, unless there is some other tricky way to get it.

Okay so for the 12kg block, we have:

m1g going DOWN
n1 going UP
T to the LEFT
fs to the LEFT

And for the 7kg bracket, we have:

m2g going DOWN
n2 going UP
n1 going DOWN
T to the RIGHT?
fs to the RIGHT

Apparently I didn't draw them correctly because when I try to solve for something, there are always two variables... other than f = Mu*N which equals 94.08 N.

Last edited by a moderator: May 4, 2017
2. Sep 23, 2009

### notbynumber

Did I mention this is due soon? Please everyone, I really need your help.