Need help please with pushing a block question

[hisoko]

http://img94.imageshack.us/img94/5889/physics.jpg

so I completely drew my work, as you can I need to find out the coeffiect of mu and the acceleration of the block. I did the Y and X forces and am stuck, because I have 2 unknowns with the X formula even if I sub in the Y into it. Am I doing somthing wrong or missing somthing here? Thanks for your help :)

 

[rl.bhat]

Your approach is correct. Post the exact text of the problem.

 

[hisoko]

The site is down for my homework assignment, but that is indeed all they gave me, they only told me the force that is pushed against the block, the angle, and the weight of the block(1000N) and I am to find mu and acceleration of the block, They then say what is the acceleration of the block if you pull it with the same force and angle, using the same mu from the push. Ill post the question as soon as the site is back up

 

[rl.bhat]

Now it is clear. Block will just start moving when frictional force fr is equal to F*cos20.
Now μ = fr/N. You know N and fr. Find μ.
When you pull the block with the same force, you can see that the normal force decreases.