What is the Normal Force (F_{N})?
The common meanings of the word "normal" do not apply. In the case of the Normal Force what is actually being described is geometry.
If two lines are at right angles to each other, we call them perpendicular.  
If two surfaces are at right angles to each other, we call them orthogonal.  
If a surface and a line are at right angles to each other, we say the line
is normal. So any line that is at a right angle to the surface is
called a normal line. If there is a force coming from the surface and at a right angle to the surface then we call it a Normal line. Any force coming from the surface and acting at a right angle to the surface is called the Normal Force. 
When an object is sitting on a level surface then the normal force is always equal and opposite of the weight of the object.  
On an inclined surface notice that...

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