Question

The coefficient of kinetic friction between a couch and the floor is 0.81. if the couch has a mass of 71 kg and you push it with a force of 650 n, what is the net force on the couch as it slides?

a: 696 n
b:86 n
c: 46 n
d:331 n

Answer 1

The answer is B. I just took the test on apex.

Answer 2

B: 86 N

Step-by-step explanation:

There are four forces acting on the couch. Weight pulling down, normal force pushing up, your applied force to the right, and friction opposing you to the left.

In the y-direction:

∑F = ma

N - W = 0

N = W = mg

In the x-direction:

Fnet = P - Fᵣ

Fnet = P - Nμ

Fnet = P - mgμ

Given P = 650 N, m = 71 kg, g = 9.8 m/s², and μ = 0.81:

Fnet = 650 - (71)(9.81)(0.81)

Fnet = 86 N