Simple block kinematics problem

[jean28]

Homework Statement

Block A weighs 75lbf and the coefficients of static and kinematic friction between A and the plane are both 0.50. Determine the acceleration of A under the action of the 25 lbf force when the velocity at A is (a) 8fps up the plane, (b) 15 fps down the plane. (c) Zero.

Homework Equations

Sum of all forces = mass * acceleration

The Attempt at a Solution

I don't know where to start... the box is doing up a plane and it's cosine is 4/5 and its sine is 3/5.

 

[HallsofIvy]

"Its cosine is 4/5 and its sine is 3/5". What is "its"?? Yes, I understand it is an angle but with the horizontal or vertical?