I don't know what you are talking about now. No one has mentioned a PM machine. We have been talking about a cart powered by the wind.
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Merged DDWFTTW in a “Real” Wind
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I don't know what you are talking about now. No one has mentioned a PM machine. We have been talking about a cart powered by the wind.
Jack by the hedge
Safely Ignored
You are bizarrely ambiguous and misleading about the lever.
Declaring that "Work in = Work out, Force in = Force out" is misleading because it sounds as if you are saying the work and force applied by the man are equal to the work and force applied to the rock, which is wrong.
When one talks about force in and out of a lever, why would anyone not intend that to mean F1 and F2?
PS Re. the sign of F2: do you contend that F1 + F2 + F3 = 0 in your example?
Are you saying that F2 is not applied to move the object vertically?
So, there must be a reaction to that. Where does that go?
If you say there is no force from the fulcrum then why do you need it?
What is the force on the fulcrum when there is not motion of the lever?
Why it is the normal force. And what will happen when the load accelerates?
No fulcrum, no lever.
http://en.wikipedia.org/wiki/Kirchhoff's_circuit_laws
Force is analogous to current. What goes, in comes out.
And you are hoping to convince me that you understand the cart, because you "get it"?
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Yes. humber told me long ago that he had alexia. He later claimed that it was his father that had alexia - not him. And later claimed it was just a test to see if I would tell others.
Of course it was not a test, and it was not his father. I think it's pretty evident to most everyone here that humber has brain-damage. That he lies almost continuously is just an added bonus.
That's right - don't expect to see any videos that prove me wrong - because even if I were wrong, humber cannot do any tests or post any videos. Apparently I "refused" to do his ill-defined tests, whereas he simply chose not to(?).
CORed
Penultimate Amazing
Yes, it is a beginners error, and it was you who made it, not me.
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Jack by the hedge
Safely Ignored
I am saying for your sum of forces applied to the lever to sum to zero, it is logically consistent to apply F2 down and teh force acting on the rock is -F2.
If I ever say anything that stupid you are welcome to ask me that stupid question.
(Neglecting the mass of the lever and assuming it is supporting the rock) F3. Which in your example is F1 + (-F2).
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And would you like to expand on that? You PM'ed me, appealing for detente. Amongst the pleading, was that you did not understand what I said, so, I threw you a pacifier at my expense. That is my father you are ridiculing, but forum rules limit expression of what I think of that.
But, your reaction to my reply was to post that PM. And have done so several times since.
And that is how you deal with criticism on your "ideas"?
Your response does show that you would indeed hide any video that was not to your benefit.
But, you DID refuse. Why would you not take the opportunity to so easily prove you were right?
There is ample evidence that you would simply discount what I produced. If you do it, you can't do that.
This video uses a rotor that is built for the task at hand, and not one from a model plane, designed to work at thousands of RPM.
http://img816.imageshack.us/img816/6015/ql0.mp4
The sum of the forces remains constant as F1. Choose whatever sign you like, but be consistent.
There is no lever on the cart, and work in = work out. Even the simplest of lever articles will tell you that.
You are confusing statics and dynamics.
E pur si muove!
Your prop is so bad that it fails.
Where is the measured data for your prop?
We have a "claim" of 200N for that, but also a "claim" of "the torque of Corvette"
650ft-lb = 881n.m
r = 0.31 ( 30 in wheel)
F_ground = 2841N
Chart says 32N
I expect the same level of absurdity for the prop.
In fact, it delivers 3W at 15rpm. Measured from your own video.
Would you like to show that you can refute the above?
I can emulate your model cart and make it go either way.
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Humber you have been shown the correct torque calculation. Stop making yourself look foolish.
Lies and delusion - alive and well in the humberverse.
CORed
Penultimate Amazing
I'm not confusing anything. It was you who cited Newton's third law (incorrectly) as "proof" that the wind could not start the downwind cart.
ETA: Apparently I'm no longer on "ignore".
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CORed
Penultimate Amazing
Yes, but those calculations were made by lying carteers. Clearly the numbers that humber pulls out of his posterior are more accurate.
Jack by the hedge
Safely Ignored
If the sum of forces acting on the lever is F1 and not zero, then why does it not accelerate without limit?
Yet there is gearing, which is an equivalent force multiplier.
That is not in dispute.
Looks that way.
Are you denying that if the cart is not moving, that the force of the wind must be met by an opposing force to produce a net of zero?
When accelerating, then f=ma, and inertia solves the apparent riddle.
But, the cart does stall, and that is evidence that one force is balanced against another. It is only assumption that says the rotor is actually doing much. Must be, right? It's big and who would make such a mistake as to forget about the wind force on the body?
Since when does constant imply zero?
There are references that will tell you of the fulcrum force, which you now seem to agree must be there. Unlikely to be a random force, but related to the others.
Work in = work out
F1*d1 = F2*d2
d changes, to increase F2, but the lever is solid, so how can F1 be different from F2? If you push one one end of a stick, then the same force appears at the other end.
The force comes from the fulcrum. It does no work, because it doesn't move.
Jack by the hedge
Safely Ignored
Since Newton.
f=ma
Constant velocity implies zero net force. Or do you disagree with Newton's second law?
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