Perhaps humber just needs a moment to realize that the force from a parachute is drag, so one formula is all he needs to cite.
The linear force (or nearly linear) involved is the rolling resistance of the cart.
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Split Thread The validity of classical physics (split from: DWFTTW)
- Thread starter Dan O.
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Perhaps humber just needs a moment to realize that the force from a parachute is drag, so one formula is all he needs to cite.
The linear force (or nearly linear) involved is the rolling resistance of the cart.
Well, here we are, one month and 3000 posts into this topic. Maybe we should have a list of what has been covered so that we can just refer to a number rather than going through the same arguments again, just for humber.
Then again, it might be easier to make a list of what humber has learned.
1) "Windspeed is stand still, in still air."
2) Aircraft fall out of the sky at windspeed.
Anything else?
Then again, it might be easier to make a list of what humber has learned.
1) "Windspeed is stand still, in still air."
2) Aircraft fall out of the sky at windspeed.
Anything else?
Last edited:
Furcifer
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Er, no. That's what you were told. It's also the reason you were the tallest kid in the class till you were in Gr. 10.
The boundary layer has no effect on the cart, on the road or on the treadmill. If you think otherwise, feel free to explain how
Yes! Blood and Fire!
John Freestone
Graduate Poster
I think he still disputes 2.Well, here we are, one month and 3000 posts into this topic. Maybe we should have a list of what has been covered so that we can just refer to a number rather than going through the same arguments again, just for humber.
Then again, it might be easier to make a list of what humber has learned.
1) "Windspeed is stand still, in still air."
2) Aircraft fall out of the sky at windspeed.
Anything else?
Oh Humber, Humber Humber Humber Humber, how embarrassing. Now how could we ever determine if drag is proportional to velocity or velocity squared? It would seem that there is a huge difference. Can anyone think of an experiment which could provide measurements we could rely on? Would Humber ever believe the results of such experiments?
Please explain Humber. If you are correct that aerodynamic drag force is proportional to the relative velocity between air and object, and can show it to be true, I want to work for you. Please please please show us how.
On the other hand, there may be unexpected and unhealthy side effects.
And yet you did state "relative velocity of chute and wind" didn't you? I suppose this is to be your escape clause since it is ambiguous and essentially meaningless, just like everything else you write.
I suppose you didn't define what "force" you were talking about either, and you never will define your terms, then make reasonable statements using them. This is your problem. This is why you can never win an argument. You may see it as a way of never losing, but in reality there is never an actual argument. You can't form one. You are only a sideshow, occasionally funny and entertaining, yes, but overall completely useless for the present purposes.
CORed
Penultimate Amazing
I think both the LCD's and the drill bit were designed by firms in the building where Humber works on the cleaning crew.
CORed
Penultimate Amazing
He apparently doesn't understand how the tags work in this forum any better than he understands basic physics.
Be careful what you wish for semper... it would seem that Humber is correct if it's a very small object and/or not moving very fast at all relative to the air (so that the flow around the object is essentially laminar instead of turbulent). See more here or here. Perhaps Humber is thinking of John Freeman's little man flying a teeny weeny kite in the boundary layer of a pixie's treadmill?
I'd like to see some data for cart sized objects and treadmill type speeds to see how close the different approximations are to reality.
Dan O.
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- 13,594
Well, here we are, one month and 3000 posts into this topic. Maybe we should have a list of what has been covered so that we can just refer to a number rather than going through the same arguments again, just for humber.
Then again, it might be easier to make a list of what humber has learned.
1) "Windspeed is stand still, in still air."
2) Aircraft fall out of the sky at windspeed.
Anything else?
Make the list of things where humber is wrong then strike through each item as he figures it out. This way we will all be reminded where he needs help if anyone decides to try and help him.
Be careful what you wish for semper... it would seem that Humber is correct if it's a very small object and/or not moving very fast at all relative to the air (so that the flow around the object is essentially laminar instead of turbulent). See more here or here. Perhaps Humber is thinking of John Freeman's little man flying a teeny weeny kite in the boundary layer of a pixie's treadmill?
I'd like to see some data for cart sized objects and treadmill type speeds to see how close the different approximations are to reality.
Yeah, ok, we should always be careful to generalize, and we won't expect drag to follow a continuous curve nor be linear across all domains or intervals. And more is the point about defining terms and conditions.
BTW the very best resource I know of for fluid mechanics;
http://web.mit.edu/hml/ncfmf.html
Priceless old films, I'd love to know what Humber thinks of them.
sol invictus
Philosopher
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- Oct 21, 2007
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- 8,613
I'm almost certain that linear in v regime never applies to cart-sized objects in air. The calculation I mentioned is very simple, and I don't see how it can be far wrong under reasonable conditions.
That does not matter so much. It is only an approximation for this esample.
It is not correct to assume that the rolling resistance is linear. There will be drag with the air and that is at least V^2.
The principle still applies.
You're funny.Er, no. That's what you were told. It's also the reason you were the tallest kid in the class till you were in Gr. 10.
Lifts the wheels. Shows that wind is not equivalentThe boundary layer has no effect on the cart, on the road or on the treadmill. If you think otherwise, feel free to explain how
Wrong again. The force of the wind on the chute or balloon is proportional to the difference is wind ans object velocities. There is opposing drag of the chute itelf, so that limits the velocity, even without a load.
Not drag, force. References have been given.
That was worth the effort.
I don't think you have made one successful point.
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