What has more friction wet or dry surfaces?

Answer 1

I'm no expert, but from just my observations, it seems that it depends on what is happening between the surfaces that are either wet or dry. example: a sandboard which people skim on the sand with a thin layer of water between the board and the sand offers little resistance and allows the rider to skim over the sand smoothly. without the water, this would be impossible as the board would dig into the sand and the rider tossed off. the same with a 'slip and slide', that toy kids wet down and slide on a sheet of plastic. that also uses water as a thin layer of lubricant. however, if the water depth were increased, the person would not slide as fast, as in the end of a water slide they increase the depth of the water to slow the rider down.

but for a different approach to this, i now bring up a motorcycle. it has tires rotating on a dry asphalt surface which also rotate on bearings between the wheel and the axle. on a slight grade, it will roll well as the friction acting upon the bike and rider is mainly the tire's friction upon the dry asphalt, the wind that both bike and rider are passing through, and the mechanical friction of the bearings in the wheels, the chain on the sprockets (and let's just say that the bike is in neutral), each individual link in the chain, and the friction of the bearings supporting the front countershaft sprocket. but just for this experiment, let's say that the chain was removed from the motorcycle so it can roll as freely as possible without any friction from drivetrain. if the road is dry, it will roll a certain distance at a certain speed. there is also the humidity in the atmosphere which for the sake of this experiment we will leave constant. if the road has a very slight coating of water on it where it is wet but not to the point where drops are adhering to the tire and being flung off, the bike rolls slightly faster and farther. add a little more water to the road and now the tire is very wet, water is being flung off the tires and the bike does not roll as fast or as far. add a lot of water and the bike's speed is noticeably slower. i think that surface tension on a larger volume of water helps create more friction than a minute amount of water.

i'd also think that an airplane that is flying with a thin coating of water on its surfaces would have more aerodynamic drag due to weight, altering the shape of the smooth surfaces which creates non-uniform and chaotic air turbulence behind the moving object.

this is a tricky question and the answer (which i am not sure i even have provided anything useful to you) is that it depends on the thickness of the water. my examples tried to cover both an object in motion, one without bearings, and one with bearings.

i am no expert, barely graduated high school, but i saw that this had no answer and want to help what i can. i know there's a lot of college and professional people out there that are going to blast this right out of the air, but that is good for it will prompt them to write a more accurate and helpful article, which the person asking the question wanted in the first place.

my best to you all.