Answer:
Multiplied.
Explanation:
I have a positive feeling about my answer. If I'm wrong, I am terribly sorry!!!
Answer:
the force of friction = fk = (uk)n = 402(uk)
the net force acting to accelerate bookcase = ma = (41)(0.12) = 4.9 N
the {assumed horizontal} push force = 65 N
so
65 - fk = 4.9
fk = 65 - 4.9 = 60 N
uk = 60/402 = 0.15 <= ANS