A 2kg block is resting on a rough incline which is at a 30 degree angle.

Question

Which is larger, the normal force or the force of friction?

Answer 1

It depends on the value of the coefficient of static friction between the 2 surfaces in contact.

 

f = force of friction

N = normal force

μ = coefficient of static friction

 

f = μN

 

So if μ < 1, f < N; if μ > 1, f > N.  Usually, μ is of the order of 1 and slightly less than 1, so f will be smaller than N in most cases.  But there are contact surfaces that have a μ > 1, and in those cases, f > N.  The mass of the block and the tilt of the plane impact N, but do not impact the fundamental relation that

 

f = μN.