Static vs. Kinectic Friction (Terminology)

[OregonTrail]

So I've seen people using terms like, "smooth", "fast", "clickly", "slippery", "tight" and "loose" to describe a cube.

How do these terms relate to the physical concepts of static and kinetic friction? Does a smooth cube have a low static friction, but it can only be considered fast if it also has a low kinetic friction? Or is a smooth cube simply one that has a very similar static and kinetic friction?

The main ways to change the feel of a cube are adjusting the tension on the central mechanism and lubricating the pieces. How can these methods adjust the feel of a cube?

There are other factors to consider, such as tracks on the pieces and the quality of the plastic. How do these affect the qualities of the cube as listed above?

Essentially, what do these terms mean? If you can think of any more let me know.

 

[qqwref]

Well, static friction affects how hard it is to initiate a turn, whereas kinetic friction affects how hard it is to keep a turn going, or how much force you need to get a turn to go a certain angle. I think static friction is usually pretty low for a lubed cube, but if a cube is "clicky" (higher static friction in a position where no layers are misaligned) or tight it tends to have higher static friction. This isn't necessarily a bad thing - cubes that are clicky and tight are less likely to accidentally misalign, so on a big cube or something with a ton of layers (like megaminx) this can actually help to prevent lockups.

As for kinetic friction, since it affects how much force you need, I think that is the source of how fast a cube feels. A really slow cube will require you to push for the entire turn, whereas on a really fast cube you can flick a layer and it will go to the next position really quickly. Since static friction and kinetic friction are affected by different things, not all tight cubes are slow and not all loose cubes are fast.

Smoothness is a combination of how smooth a cube literally is internally and how lockup-prone it is (which is affected by static friction, which affects accidental misalignments, and by the springs and cubie curvature, which affect how much the cube can be misaligned without locking). I don't know of any reasonable way to quantify how smooth a cube is. Some loose cubes are a lot smoother if you handle them with less force, probably because allowing the cubies to move around a bit (rather than forcing it into a specific position) may prevent lockups by making it easier for them to move out of the way of a turn.

 

[LewisJ]

my thoughts:
"smooth" - similar kinetic and static, also generally at least decent cornercutting
"fast" - low kinetic
"slippery" - low static and not very high kinetic
"tight" - high static friction, not low kinetic, probably doesn't cut corners that great
"loose" - low friction in general, probably cuts corners well but also probably locks up a bit much
clickly - not too sure.