Was moving across the top, the fact that this fluid What do I mean by that? I mean that when this lid The fact that this fluid's in here now is resisting the motion You give it another nudge, it slows down and stops. It doesn't keep going, it slows down and stops. Now what happens is you take this lid, you go to slide it across again. And I'm gonna fill it to the brim all the way to the top. Let's say there is no resistance so that if I gave this lid a little nudge, it just keep moving Now, check out this lid that I can put on the empty box.
#Viscosity of honey in pascal seconds skin#
Which shows how naïve we all are-what in the world is skin friction!? Internal friction is the force resisting motion between the elements making up a solid material while it undergoes deformation. Skin friction is a component of drag, the force resisting the motion of a fluid across the surface of a body. Lubricated friction is a case of fluid friction where a lubricant fluid separates two solid surfaces.
Dry friction is subdivided into static friction ("stiction") between non-moving surfaces, and kinetic friction between moving surfaces.įluid friction describes the friction between layers of a viscous fluid that are moving relative to each other. You can't expect a simple equation to describe all instances of that behavior.ĭry friction resists relative lateral motion of two solid surfaces in contact. Basically electrons from different surfaces interact and create resistance.
.jpg "viscosity of honey in pascal seconds")
The force is really caused by quantum phenomena, the electromagnetic force. It's just that usually when you're talking about friction (such as air resistance) you don't usually think about layers of fluid but instead simplify the force as proportional to an object's velocity, such as F = k v or F = k v^2.į = μ N is just an approximation and only applies to dry friction. It may still be hard to believe there is zero resistance, but even if there was another resistance force, by definition it is not the viscous force, but some other force we had assumed didn't exist. The "inertial drag" has nothing to do with velocity, only acceleration, and therefore is not viscosity. But still, you can't blame the mathematics.īesides, if the board and water are already moving, there sure is no resistance. So the water increases inertia, but doesn't provide a resistance force.Įxcept with a depth of infinity the mass would probably be infinity too, so it would be impossible to drag the water (a = F/m = F/∞ = 0). If the board is 1 kg, the water is 2 kg, and the force pushing the board is 6 N, then acceleration is not 6 N / 1 kg = 6 m/s^2, as is the case when there is no water, but 6 N / (1 kg + 2 kg) = 2 m/s^2, with a = F/m. However, by dragging the water with us we need to conquer its inertia.
There is no force preventing that because there is no "ocean floor" to provide the friction, and we are assuming there is no other resistance. I think if the depth were really infinity, there would be no friction, because we could perfectly well drag all that water with us.
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