What Went Wrong in My Incline Friction Problem?

[houseguest]

Hello, this is a physics problem I worked out an cannot determine what I did wrong.
Attached is the problem and my solution. Any help would be very appreciated.
Thanks.

Homework Statement

Attached

Homework Equations

F = ma, f_k = Mu_k * N, dx = v0t + 1/2at^2

The Attempt at a Solution

Attached

 

[houseguest]

image

It's been pending approval for longer than my patience. I got imageshack to host.
URL: http://img88.imageshack.us/my.php?image=prb1gr7.jpg

Thanks

 

[Doc Al]

Looks to me that you assumed the force of the rope on the mass was equal to the weight of the hanging mass. That's not true. (If it were true, the hanging mass would be in equilibrium.)

Instead, call the rope tension T. Apply Newton's 2nd law to both masses, then combine the equations to solve for the acceleration.

 

[houseguest]

Ooooh yeah. Thanks!