Is it really friction, though? It seems to more like a case of one layer inducing mechanical work in the other, which in turn results in loss of efficiency due to inertia and actual friction within the layer.

In other word, I read this akin to an inductive coil moving through a magnetic field and drives a motor with a load. This will cause the coil to resist the movement, but it can hardly be called friction.

What is your understanding of friction?

My uneducated understanding/intuition: Mechanical resistance to movement between two surfaces that touch. This resistance is partially caused by imperfections in the two surfaces that cause the surfaces to slightly mesh. Also, partially, I am sure there’s some electromagnetic laws at play on the molecular level that resistance the movement.

You brushed against the real truth there. Haha. Stupid joke, sorry.

The truth is that surfaces never “touch”. How do you touch an atom? Even an atom in a tight lattice or molecule is held in place only loosely by electromagnetic forces. The electron shells are a convenient idea more than they’re real, they’re not a real boundary for another atom to bump against. And the nucleus is so much tinier than the innermost shell it’s hard to wrap your mind around.

Basically, surfaces don’t truly exist. In reality the surface is just a fuzzy area where things are limited in how close they can get before the forces between the electromagnetic layers push back.

So friction is just when one electromagnetic fuzzy thing interferes with another electromagnetic fuzzy thing’s lateral motion, and that interference atom to atom creates movement in the lattice of each which creates heat.

This finding is just that in special circumstances those electromagnetic fuzzy things can be a lot further apart when they interfere with each other.

This finding is just that in special circumstances those electromagnetic fuzzy things can be a lot further apart when they interfere with each other.

Reading the article it seems this research is about Amonton’s first law which is about the way friction increases with load. This experiment shows that in certain scenarios the friction can be low when the distance is close or far but at a medium distance (not sure the exact distances here) the friction increases thus breaking Amontons’ first law.

Although the magnetic interaction, i.e. the normal load between the two layers monotonically decreases with increasing h, 〈Fₓ〉exhibits a clear peak around h₀ = 9 mm. This is in strong contradiction with Amonton’s empirical first law, which claims that sliding friction is proportional to the load 33.