A block sits on the floor.
(a) What is the magnitude of the frictional force on it from the floor?
(b) If a horizontal force of 5 N is now applied to the block, but it does not move, what is the magnitude of the frictional force on it?
(c) If the maximum value fs,max of the static frictional force on the block is 10 N, and you apply a 12 N force, what is the magnitude of the frictional force?