Inclined Plane Problem-- Solving for Theta

[drdevil52]

Homework Statement

These two problems are inclined plane problems which I cannot figure out. The problems are attached in the image below.

Homework Equations

Fnet=ma

The Attempt at a Solution

I first broke down the gravity force into its x and y components. After that, I did this:
mgsinx-F(kinetic friction)=ma

and found the expression for normal force: N=mgcosx

then found the expression for F(kinetic friction): mgcosxµk

I tried plugging in the expression for kinetic friction:

mgsinx-mgcosx(µk)=ma

I wasn't able to find an answer using this method so now I have no clue how to proceed.

 

[Spinnor]

The important part of the question says (the print is too small for my eyes) the angle is adjusted so that the block has a constant speed of (can't read it) call it v.

Assume your equation is correct, what is the acceleration if the velocity is constant?

 

[drdevil52]

Oh I see, I completely overlooked that-- I mistook the velocity for acceleration. I'll rework this with a=0 and see if I can figure it out. Thanks!