TBR: Air Resistance Only For Moving Objects

[justadream]

---

Members do not see this ad.

TBR page 118 #45

Why is air resistance only considered for moving objects?

Like let's say an object sits on a frictionless surface angled at .000001 degrees in a container with huge amounts of pressure (the air).

So the compressed air wouldn't be able to keep the object from moving if the object is initially stationary?

Maybe I'm discussing another type of friction?

EDIT: Meant to post in Q&A section. Sorry!

 

[Thoroughbred_Med]

Yeah, that's a unique scenario you presented.

Just know that air resistance is an opposing force, drag, and must act accordingly in response to another force (gravity)

 

[AmishExpressWay]

While air does affect stationary objects, that effect produced is buoyancy and not air resistance. Buoyancy due to gases are basically null, unless you got some badass gas like sulfur hexafluoride:



Air resistance on the other hand is resistance to movement. Air and water have weak and strong intermolecular forces respectively and provide different amounts of resistance in the way of viscosity. Logically speaking, air resistance increases with speed because you are breaking more and more intermolecular forces per second the faster you move through a fluid (or gas). Therefore, a friction like force, drag, is produced which works to slow down movement.

So, to answer your question, buoyancy is for stationary objects and depends on the difference in densities of the object and gas.

 

[SN2ed]

Thread closed. These types of questions belong in the MCAT Study Q&A forum.