Simple forces described in terms of fundamental forces

[SamRoss]

TL;DR

How can non-fundamental forces such as friction and tension be described in terms of fundamental forces?

My first question is actually, what happens when any two objects get near each other? This question is often phrased as "Why can't you really touch anything?" or "Why can't you walk through walls?" I have heard two answers: 1. the repulsion between electrons 2. the Pauli exclusion principle. Which of these is correct or are they both right?

Once that's settled, how can each of the following forces be described?
Friction
Normal
Air resistance
Applied
Spring
Muscular
Tension

Is it fair to say that the first five (friction through spring) are really just the same as my first question - that is, due to electron repulsion or the Pauli exclusion principle? How would tension and muscular forces be described on a fundamental level?

 

[Drakkith]

My first question is actually, what happens when any two objects get near each other? This question is often phrased as "Why can't you really touch anything?" or "Why can't you walk through walls?" I have heard two answers: 1. the repulsion between electrons 2. the Pauli exclusion principle. Which of these is correct or are they both right?

The PEP keeps matter from potentially collapsing into a super-dense state except under enormous pressure, while the repulsion between electrons keeps one solid object from passing through another. Both concepts, along with the attractive/repulsive forces between electrons and/or nuclei, are responsible for the ability of a solid object to maintain its shape and structure.