So, there should be two forces acting on the refrigerator: the applied force and the friction force.
The question mentioned that the friction force was set to zero, so the only effective force now would be the applied force.
We have an applied force of 400 N to the right, this means that:
<span>The magnitude of the net force is 400, directed to the right.</span>
The kinetic energy before equals K after
The answer is underground