Pulling a block along a surface using a string inclined at an angle

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Memo
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Homework Statement
A block with a weight of P is being pulled by a string of length l at a constant rate and an angle. The distance between the tip of the block to the surface is h. (see the photo below)
Find the kinetic coefficient of friction (the string is attached to the centre of the block)
Answer hint: k=(F*sqrt(l^2-h^2))/(Pl-Fh)
Relevant Equations
f=k*N
Diagram of a rectangular block on a horizontal surface, with a string of length l attached to its front point and pulled up and to the right by force F at an angle, with vertical height h marked on the right.

Handwritten free-body diagram of a block with force F at angle alpha, showing components Fx and Fy, normal N, weight P, and friction f, followed by working for N, Ox and Oy equations, and the derivation of k.
 
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Discussion

Memo said:
The tension force along the string is equal in magnitude and opposite in direction to the force being applied
I don't understand this. The tension is ##\vec F## and has the same magnitude and direction.
Memo said:
Can I put Fx=sqrt(l^2-h^2) and Fy=h?
No you cannot. It says that a force is equal to a length which is never true.

Try getting two equations, saying that vertical and horizontal components of the net force are zero which is always true when the acceleration is zero.
 
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kuruman said:
I don't understand this. The tension is ##\vec F## and has the same magnitude and direction.

No you cannot. It says that a force is equal to a length which is never true.

Try getting two equations, saying that vertical and horizontal components of the net force are zero which is always true when the acceleration is zero.
I watched a somewhat relevant YouTube video and saw there was also the tension force, so I included it. But I've my problems, thank you so much!
 
Your solution looks correct. For future reference, please don't edit the original post because it can be confusing to people who have seen it and are trying to respond to it. Corrections or additions to the first post should be posted separately.

Also, you are encouraged to use LaTeX to write equations. It's a useful skill and makes everybody's life much easier. Click on the link "LaTeX Guide" (lower left above "Attach files") to learn how.