Find the acceleration with very little

[Buckler]

Homework Statement

The problem i have to do is i have to find the acceleration of a box with unknown weight on a decline plain that has a length of 4.5m and an angle of 22 degs. the box has a kinetic friction at the end of the ramp of .12 .
how would u calculate this?

Homework Equations

The Attempt at a Solution

 

[Doc Al]

Figure out the net force on the box and apply Newton's 2nd law.