What force opposes motion in a fluid?

Answer 1

Two mechanisms oppose motion in a fluid: viscosity and turbulence. Viscosity is sort of the fluid equivalent of friction and is the result of the fluid rubbing against itself and the objects in contact with the fluid at the molecular level. In an ideal fluid, the force caused by viscosity is proportional to the velocity of the object moving through the fluid.

Turbulence also opposes motion in a fluid. The motion stirs up the fluid into eddies and vortexes that eventually dissipate through viscous drag, often big enough to be visible to the naked eye. The braking force caused by turbulence is proportional to the square of the velocity of the object moving through the fluid.

Turbulence, unlike viscosity, often causes visible fluctuating irregularities in the surface of a fluid. A slow-flowing stream may have almost a glassy smooth surface, perhaps with the occasional (turbulent) eddy, but the surface of a rushing stream is anything but smooth and may even produce considerable (acoustical) noise as it moves along.

Answer 2

1. The inter molecular friction of liquid.
2. When the speed is high, the force (or energy) required to displace the liquid.
3. Owing to the second factor, the opposing force for low speed is proportional to speed, for higher speeds it is proportional to the square and even cube of the speed.

The formula for friction is already given in some other answer.

Answer 3

The force that opposes motion in a fluid is a type friction. In air, we call this air resistance. In water, it is called water resistance.

Answer 4

Friction is the force that opposes motion.

If you are talking about air as your fluid, we would more commonly call it air resistance.
In a liquid, there is still friction with the particles of the liquid.

Answer 5

Viscous force is the answer. The basic difference between friction force and viscous force is that viscous force depends upon the area while friction force does not.The magnitude is = 6 pie n r v. n=viscousity of fluid.

Answer 6

Drag forces oppose action by using a fluid. the main important properties of the fluid which impact its drag are its viscosity (stickiness) and its density. that is extra convenient to generate raise in fluids of better density and of better viscosity. by using extra convenient I mean you do no longer would desire to bypass so quickly to generate a given particular raise stress. subsequently a water skier can stay awake on 2 small boards on water yet to accomplish that interior the air desires plenty extra section - a parachute.

Answer 7

the force is given by stokes law f=6pi n r v