Friction

[AzonicZeniths]

I was just wondering, because on an atomic scale, nothing ever touches due to electron repulsion, why is there friction?

[pixel01]

Friction forces occur at larger scale, not that tiny.

[russ_watters]

Even when not touching, there are still forces (electromagnetic) between objects. It isn't like every surface is a mag-lev train - surface defects mean the forces aren't perpendicular to the direction of motion.

[AzonicZeniths]

Ok I now understand that this the forces aren't perpendicular, but why would this produce heat? Where is the energy being released?

[russ_watters]

The heat is due to the fact that the interactions are not perfectly elastic.

[AzonicZeniths]

perfectly elastic.

Sorry I'm being stupid right now but, what do you mean by that?

[rock.freak667]

Sorry I'm being stupid right now but, what do you mean by that?

a perfectly elastic collision is one in which kinetic energy is conserved.