Dynamics: Minimum Force Problem

[JM92]

Hi, nice to meet everybody here at physicsforums.com! I'm JM92 and I have a physics problem I need help with.

Homework Statement

Find the smallest value of the mass M for which the system will remain at rest given that the coefficient of static friction is 0.100
[PLAIN]http://img695.imageshack.us/img695/6328/physics2.jpg

Homework Equations

F_net = ma
∑F(Horizontal) = 0
∑F(Vertical) = 0
F_f = μ・F_N
Fg_x = Fg・sinθ
Fg_y = Fg・cosθ

The Attempt at a Solution

[PLAIN]http://img3.imageshack.us/img3/4139/physics11.jpg
I retyped and redrew everything with MS paint.. Hopefully that made it easier to read and not harder..

PS. The correct answer is 4.98kg.

Thank you for your help!

EDIT: Sorry, the thread title should be called "Minimum Mass Problem"

 

[verty]

You've drawn F_f in the wrong place. M is the mass of the second block; if it is any smaller, the first block will slide down the incline.

How small can M be?

 

[JM92]

You've drawn F_f in the wrong place. M is the mass of the second block; if it is any smaller, the first block will slide down the incline.

How small can M be?

Ohh! I was looking at it backwards, then. With F_f in the opposite direction, I got the correct answer. Thank you very much!