Are drag and viscosity the same force?

Question

After I was flying a remote control airplane, I had a picnic with my friends. One of them brought honey and this idea popped into my head.

Also, if gravity is the weakest of the elementary forces, why do things fall to earth instead of being reflected by the charge in aerial particles or the ionosphere? I know this is more of a fluid dynamics question, but I'm wondering why does it matter how many atoms there are to get in the way of another body. Shouldn't some of the atoms get trapped in between the descending body and the earth so that there's a point where the object just floats above the earth, or is air pressure what we call the resistance applied by the atmosphere's atoms which are repelling the falling object (then, as the object approaches the ground, the imperfect positioning of the air's atoms results in it getting squished out to the side from between the falling object and the ground)?

Answer 1

Good question, Mikey C!

Drag is the force of resistance created by motion through a fluid. It is a force, and in aeronautics it is usually opposed by the force generated by the engine(s), called thrust.

Viscosity is the relative thickness of a fluid. Honey and molasses are very viscous. Water is not very viscous. Air is a fluid that is even less viscous.

A more viscous fluid will produce more drag, given the same velocity.

Tryumph is right, because the earth is so very, very large even a relatively weak force like gravity is very large as well. Darn it! Would be fun to leap 100 feet into the air!

Finally, air flowing at subsonic velocities is virtually incompressible, like water. So it simply is pushed out of the way by the descending object. Seems counter-intuitive, but true.

Hope that helps!

Answer 2

Air resistance is just a form of friction acting between a solid body and a gas (air). The drag force experienced by an object is the exact same thing as this. The terms are interchangeable and can apply to a moving gas flowing past a stationary body or a stationary body moving through a gas that is at rest. The upthrust is what happens when the pressure at the leading edge (the face of the body that is at the front as it moves forward through the gas) becomes greater than the pressure at the trailing edge. The area of high pressure pushes against the object as it tries to equalise, by moving from high to low. This has the effect of slowing the body down, as does the drag force that is pulling it backwards. Therefore both of these forces are attempting to resist the force of gravity that is making the object fall. In the case of an airplane, the wing is designed in such a way that the upthrust force overcomes the force of gravity, allowing the plane to stay in the air. And to answer your other question, yes, the upthrust increases in magnitude the faster the object is moving because the pressure difference between the leading edge and the trailing edge of the object becomes greater with increasing velocity.

Answer 3

gravity is the weakest RELATIVE force, but since the mass of earth is so huge, it dominates most things around us.

drag and viscosity are not the same, because drag refers to wind resistance, while viscosity refers to liquid resistance.

Answer 4

Drag is resistance, viscosity is amount of pressure reduced by oil weight.