Dynamics of block with friction...how to set up?

fizziksc

1. The problem statement, all variables and given/known data
a 2.0 kg wood box slides down a vertical wood wall while you push on it at a 45 degree angle. what magnitude of foce should you apply to cause the box to slide down at a constant speed? I know that Mk = .2 (wood on wood)


2. Relevant equations



3. The attempt at a solution

I tried to solve it with setting the forces in the y direction. I keep getting it wrong. i said Fy=0=Fasin[tex]\vartheta[/tex] - 19.6 N then solved and got Fa = 27.71 N. however the answer is Fa = 23.1 N

PhanthomJay

You have to look at all forces in the y direction. You missed one. You're going to have to look for all forces in the x direction as well.