Aerodynamic lift- A real problem

[Frank Lee]

Like this?

http://www.youtube.com/watch?v=-i4wEx4GRcg

[Christ]

No, Frank... that's centripetal force. :P

Where do you keep them all?!?! And how do you remember them all for each specific occasion?

[Frank Lee]

Centripetal force keeps much stuff swirling around in my head cavity but sometimes something excapes

just think, throw some vgs on there, maybe a lip spoiler and that thing could almost come to a stop at the top of that O and not fall down!

[Christ]

LMAO Frank. It's a good thing I gave up and went to bed last night, else my wife would have killed me from the belly laugh I just got.

Also, I once again got those terms mixed up. It's centrifugal force that keeps the car planted toward an exterior shape. Centripetal force would keep it moving toward center, not away from it.

[winkosmosis]

I remember getting annoyed by my school teachers talking about centripetal force because it made no sense. If you're swirling a bucket around so the water "magically" stays inside, there's no centripetal force holding the bucket. It's your ARM. There's no centrifugal force either, it's just the water wanting to keep going in a straight line.

[Christ]

If you view the bucket and the water as a single object, a "bucket-o-water", it's centrifugal force that makes the bucket want to fly out of your hand, and your finger strength provides centripetal force, which retains the bucket.

The forces aren't phantom, by any means. They follow Newton3, and are equal and opposite in their application. They also don't just occur. The application of either force depends wholly on the frame of reference from which it is observed.

[winkosmosis]

My fingers don't exert centripetal force. All they do is curl in or curl out. The water doesn't know it's being pulled inward, it just wants to conserve its momentum and keep going straight.

[Nerys]

yes its just your arm holding it. but as Christ stated the words are simply ways of describing the type and application of the forces.

it would be like simply saying hey want to race a car. well that does not really help does it? if its your metro against my Lambo or your metro versus my yugo its a very different ball game ehh?

but its just a car? but its just your arm? see. thats all. its just describing the KIND and APPLICATION of the forces involved.

same with DRAG. thats the opposite people are NOT seeing the differences. they are just saying its your arm. its your car. its drag.

ie they are non equal :-)

[winkosmosis]

Originally Posted by Nerys

yes its just your arm holding it. but as Christ stated the words are simply ways of describing the type and application of the forces.

it would be like simply saying hey want to race a car. well that does not really help does it? if its your metro against my Lambo or your metro versus my yugo its a very different ball game ehh?

but its just a car? but its just your arm? see. thats all. its just describing the KIND and APPLICATION of the forces involved.

same with DRAG. thats the opposite people are NOT seeing the differences. they are just saying its your arm. its your car. its drag.

ie they are non equal :-)

So what you are saying is that the lift and downforce on either side of a teardrop or aerofoil are equivalent to centrifugal force and centripetal force, and you were wrong to say that they don't exist?

[Nerys]

I can prove your fingers exert different forces.

go find a victum. put your hand on their chest and PUSH. thats a force a force we have named PUSH.

how GRAB their shirt and PULL them toward you.

thats a force we have named PULL. they are different in type and application but the same in general. ie a FORCE exerted. Just exerted "differently"

see?

also you are simply ignorant to the forces at play (NO insult I could not find another word to use) ignorant simple as your not seeing it.

for example in order to SWING that bucket you have to exert an awful LOT of different types or forces.

for one you need to LEAV AWAY from the bucket in order not to fall toward it. you also need to ORBIT your body at the bucket spins in order to keep it from WOBBLING you.

you also need to increase the force on your fingers to retain a grip on it as you increase speed.

you need to push down and out with your feet as you twist with your arm an torso in order to retain balance.

all these things AND MORE are occurring without you even realizing it. its subconscious but it can all be explained mathematically.