It's necessary to change the particles kinetic and velocity to open external and eternal.
Due that the velocity is constant that means that friction force is equal to the force exert by you, otherwise the refrigerator will accelerate or decelerate and in both cases velocity will not be constant.
So then the friction force between refrigerator and floor is 150 Newtons.
Answer:
13.33 seconds
Explanation:
I = Q/t
t = Q/I = 4/0.3 = 13.33 seconds