Question

a person is trying to push a box along the floor, and it is starting to move. which of the following relationships are correct. $f_s$ is the static friction on the box from the floor. $f$ is the force applied by the person to the box. $f_2$ is on the person from the box. $f_1$ is on the floor from the box. a. $f = f_2$ $f = f_k$ $f_s=f_1$ b. $f>f_k$ and $f_2>f$ c. $f_2 = f_1$ and $f = f_k$ d. $f = f_2$ $f>f_k$ e. $f = f_2$ $f = f_k$ $f_k=f_1$

Explanation:

Step1: Apply Newton's third - law

According to Newton's third - law, the force exerted by the person on the box ($F$) and the force exerted by the box on the person ($F_2$) are an action - reaction pair. So $F = F_2$.

Step2: Analyze the motion of the box

Since the box is starting to move, the applied force $F$ by the person must be greater than the kinetic friction force $f_k$ acting on the box, i.e., $F>f_k$.

Answer:

D. $F = F_2,F>f_k$