Question

question 4 of 10
a man pushes with a force of 150 n on a bookcase of mass 100 kg. the coefficient of static friction between the bookcase and the floor is 0.65. because of friction, the bookcase does not move. what is the force of friction on the bookcase?
a. 980 n
b. 100 n
c. 637 n
d. 150 n

Explanation:

Step1: Analyze forces on book - case

The book - case is at rest, so the net force in the horizontal direction is zero. The applied force $F_{applied}=150\ N$ and the frictional force $F_f$ act in the horizontal direction.

Step2: Apply Newton's first law

According to Newton's first law ($F_{net,x}=0$ for an object at rest in the horizontal direction), $F_{applied}-F_f = 0$. So $F_f=F_{applied}$.

Answer:

D. 150 N