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Newton's third law problem.
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james_s:

--- Quote from: PlainName on November 27, 2022, 06:49:13 pm ---You might learn something.

--- End quote ---

Learning something is not the goal of trolling. He's obviously just yanking your chain, no real person is that stupid or dense.
electrodacus:

--- Quote from: PlainName on November 27, 2022, 06:49:13 pm ---And yet it's OK for you to copy random equations from t'web to prove ... something. Why not actually write yours from scratch instead of copying someone elses thing meant for some different scenario? You might learn something.

--- End quote ---

Not quite sure what you are talking about.  The equation is universal and is just one applicable to all of this cases.
You may make your own equations if you come up with new physics but there is nothing new in relation with what we discuss here.

The correct and universal equation for Drag Power is this that I mentioned for months here and all of you where disagreeing with.

Pd = 0.5 * air density * (area * coefficient of drag) * (wind speed - vehicle speed)3

The wrong equation that many of you are claiming to be correct is the one below,
 
Pd = 0.5 * air density * (area * coefficient of drag) * (wind speed - vehicle speed)2 * vehicle speed


Both this link https://scienceworld.wolfram.com/physics/DragPower.html  and this calculator https://www.electromotive.eu/?page_id=12&lang=en  use the correct equations so they agree with what I'm saying.
I provided those links to show that I'm not inventing new physics but that all this is known for a very long time.

PlainName:

--- Quote ---The correct and universal equation for Drag Power is this that I mentioned for months here and all of you where disagreeing with.

Pd = 0.5 * air density * (area * coefficient of drag) * (wind speed - vehicle speed)3
--- End quote ---

a) How did you derive those terms? You could post anything and say that's correct, or copy anything and say it's correct "because someone else uses it too", but unless you know how the terms were derived it's meaningless to you.

b) Which term(s) cover the propeller and wheel operation? The propeller, and connection to the wheels, is kind of super-important since it's the thing that makes it work, and yet it doesn't exist in your copied equation. How can that equation possibly account for it, then?
Kleinstein:
The formular for the drag power is the frist one, but this is the power theoretical possible to take from the wind and that is not the power needed for the vehicle to drive. The power for the vehicle is more like the 2nd formular.

It is obvious that the first formula can not be corrent for the power of the vehicle: if the vehicle changes direction from going against the wind to going with the wind it changes from needing power to drive to gaining power from the wind. So the sign in the power has to change at around 0 vehicle speed.
Another way is to look at the force need: mechnical power is force times speed, more or less by definition. The force from the wind is limited and approaching zero speed the power this also has the approach zero.

The relevant question for the vehicle is if the motor can provide sufficient force. The power only determines how fast the vehicle can go. With low speed very little power is sufficient.
bdunham7:

--- Quote from: electrodacus on November 27, 2022, 07:05:46 pm ---Both this link https://scienceworld.wolfram.com/physics/DragPower.html  and this calculator https://www.electromotive.eu/?page_id=12&lang=en  use the correct equations so they agree with what I'm saying.
I provided those links to show that I'm not inventing new physics but that all this is known for a very long time.

--- End quote ---

You've scoured the internet to find 'examples' where someone has made an error somewhere that supports your argument, but those errors are painfully obvious with just a little bit of a fair-minded consideration.

In the Wolfram example, they clearly have only considered the case where the vehicle speed is the same as the speed of the fluid relative to the body, as in driving in still air.  That is obvious simply looking at the equations.

In your other example, if you bother to read their explanations elsewhere on their website under "Vehicle Physics" they say:

Now, the propulsion power can be calculated as a product of driving resistance and vehicle speed:

But from the operation of the malfunctioning calculator app, you can see that they have not incorporated this into their algorithm. 

In neither case do they use the equation you claim they do.

The Wolfram example has at least one part right before they go and screw it up.  P = FD * Vvehicle
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