Here's why:
* Fundamental Forces: These are the basic building blocks of interactions in the universe. They are thought to be truly fundamental and can't be explained in terms of anything simpler. The four known fundamental forces are:
* Strong Force: Holds atomic nuclei together.
* Weak Force: Responsible for radioactive decay.
* Electromagnetic Force: Governs interactions between electrically charged particles.
* Gravitational Force: Attracts objects with mass.
* Emergent Forces: These are forces that arise from the collective behavior of many particles interacting through the fundamental forces. They are "emergent" in the sense that they are not fundamental themselves but rather are a consequence of the underlying fundamental forces.
Examples of Emergent Forces:
* Friction: Arises from the electromagnetic interactions between the surfaces of two objects in contact.
* Normal Force: An upward force exerted by a surface to support an object resting on it, ultimately caused by the electromagnetic interactions between the object and the surface.
* Tension: A force that is transmitted through a string, rope, cable, or similar object when it is pulled taut. It is caused by the electromagnetic interactions between the molecules of the string or rope.
* Air Resistance: A force that opposes the motion of an object through the air, caused by the collisions of the object with air molecules.
So, to answer your question directly: There's no such thing as a "non-fundamental force." What we sometimes refer to as "non-fundamental forces" are actually emergent forces that arise from the fundamental forces.
