When I push on my refrigerator, there is a force acting on it that wasn't there before. That means it should be experiencing an unbalanced force and begin to move. Why doesn't it?
The refrigerator has a bigger mass so it is not going to move because it is equal to your force
You aren't pushing hard enough.
The reason your refrigerator doesn't move when you push it is due to the presence of static friction. Static friction is a force that opposes the motion of two objects in contact with each other, but not yet in motion.
When you push on the refrigerator, you exert a force on it, but the refrigerator remains stationary because the static friction force between the refrigerator and the floor is equal and opposite to the force you applied. This static friction force acts as a balancing force, preventing the refrigerator from moving.
The maximum static friction force that can be exerted is determined by the coefficient of static friction, which depends on the nature of the surfaces in contact. If the force you apply is below this maximum static friction force, the refrigerator will stay in place.
So, even though there is an unbalanced force being applied to the refrigerator when you push it, the static friction force cancels out this imbalance, thereby keeping it stationary. If you were to apply a force greater than the maximum static friction force, the refrigerator would overcome this resistance and start to move.