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Electroboom: How Right IS Veritasium?! Don't Electrons Push Each Other??

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electrodacus:

--- Quote from: gnuarm on July 16, 2022, 05:20:12 pm ---Your idea of the "average" speed of the sail being important is irrelevant.  You know that.  The sail is impacted by the wind while it is moving on top of the car.  The rest of the time it is not interacting with the wind.

If you can't understand this, you have no claim to understanding anything in physics or math. 

Do this, split the actions on the sails into two phases.  Phase 1 is while on top of the car and moving towards the rear of the car.  Phase 2 is the rest of the time while the sails are are tiny and not interacting with the wind.

So during phase 1 the power provided by the wind on the sails is given by your equation, no?  In that case, the wind speed relative to the sail is 3/4 of the vehicle speed.

During phase 2, the power provided by the wind on the sails is zero, because the wind does not reach the sails.  So the vehicle speed does not matter.  Zero times anything is still zero.

I know you won't admit that you understand this.  But that is because you refuse to acknowledge you are wrong and are being a troll.

--- End quote ---

I just explained this to my wife and she understands the concept so I will try to simplify this as I'm sure you will be able to understand.

Say vehicle is just 0.5m long.
We replace the air with 1.2kg balls spaced 1m apart.
At some point in time the vehicle (ideal no friction) moves at constant 10m/s
The 1.2kg balls that also move at 10m/s are one behind the vehicle say 0.25m from vehicle and the other is in front 0.25m from the vehicle.
Can you get that the moving sails on top of the vehicle can not be hit by the ball traveling at same speed as the vehicle 10m/s?

If you can understand the ball example then air is the same way.
If you can not understand the ball example and still think the sails somehow can be hit by the ball then I have no idea how to help.

gnuarm:

--- Quote from: electrodacus on July 16, 2022, 05:26:55 pm ---
--- Quote from: gnuarm on July 16, 2022, 05:20:12 pm ---Your idea of the "average" speed of the sail being important is irrelevant.  You know that.  The sail is impacted by the wind while it is moving on top of the car.  The rest of the time it is not interacting with the wind.

If you can't understand this, you have no claim to understanding anything in physics or math. 

Do this, split the actions on the sails into two phases.  Phase 1 is while on top of the car and moving towards the rear of the car.  Phase 2 is the rest of the time while the sails are are tiny and not interacting with the wind.

So during phase 1 the power provided by the wind on the sails is given by your equation, no?  In that case, the wind speed relative to the sail is 3/4 of the vehicle speed.

During phase 2, the power provided by the wind on the sails is zero, because the wind does not reach the sails.  So the vehicle speed does not matter.  Zero times anything is still zero.

I know you won't admit that you understand this.  But that is because you refuse to acknowledge you are wrong and are being a troll.

--- End quote ---

I just explained this to my wife and she understands the concept so I will try to simplify this as I'm sure you will be able to understand.

Say vehicle is just 0.5m long.
We replace the air with 1.2kg balls spaced 1m apart.
At some point in time the vehicle (ideal no friction) moves at constant 10m/s
The 1.2kg balls that also move at 1m/s are one behind the vehicle say 0.25m from vehicle and the other is in front 0.25m from the vehicle.
Can you get that the moving sails on top of the vehicle can not be hit by the ball traveling at same speed as the vehicle 10m/s?

If you can understand the ball example then air is the same way.
If you can not understand the ball example and still think the sails somehow can be hit by the ball then I have no idea how to help.

--- End quote ---

Yes, I understand that you screwed the numbers.  Here are the correct numbers.

Car is moving 10 m/s.  Sails are moving 2.5 m/s.  Wind is blowing 5 m/s. 

Now the sails receive a 2.5 m/s wind and can easily propel the car.

Can YOU understand this?  I explained it to my cat and she understood it quite well.

electrodacus:

--- Quote from: gnuarm on July 16, 2022, 05:39:36 pm ---
Yes, I understand that you screwed the numbers.  Here are the correct numbers.

Car is moving 10 m/s.  Sails are moving 2.5 m/s.  Wind is blowing 5 m/s. 

Now the sails receive a 2.5 m/s wind and can easily propel the car.

Can YOU understand this?

--- End quote ---

I have not screwed the numbers just used the simplest example so you can understand.
As for your new numbers think in the same way with 1.2kg balls spaced 1m apart.
The sail (front side) will hit those balls not the other way around.
It is relevant to know if ball hits the sail or sail hits the ball to know what happens with vehicle kinetic energy and thus also vehicle speed.

gnuarm:

--- Quote from: electrodacus on July 16, 2022, 05:47:05 pm ---
--- Quote from: gnuarm on July 16, 2022, 05:39:36 pm ---
Yes, I understand that you screwed the numbers.  Here are the correct numbers.

Car is moving 10 m/s.  Sails are moving 2.5 m/s.  Wind is blowing 5 m/s. 

Now the sails receive a 2.5 m/s wind and can easily propel the car.

Can YOU understand this?

--- End quote ---

I have not screwed the numbers just used the simplest example so you can understand.
As for your new numbers think in the same way with 1.2kg balls spaced 1m apart.
The sail (front side) will hit those balls not the other way around.
It is relevant to know if ball hits the sail or sail hits the ball to know what happens with vehicle kinetic energy and thus also vehicle speed.

--- End quote ---

Of course you screwed the numbers.  You know this clearly shows you to be wrong, so you have to "simplify" it to a point where you have constructed an example that breaks.  It's not the concept that is broken, just YOUR example. 

I can fix your example very easily.  First your typo has to be fixed.  "The 1.2kg balls that also move at 1m/s" should be "The 1.2kg balls that also move at 10 m/s", no? 

Then change the spacing of the balls from "1 m" to 0.1 meter.  Now the balls will hit the sails and the car will be propelled faster than the wind. 

electrodacus:

--- Quote from: gnuarm on July 16, 2022, 06:12:18 pm ---
Of course you screwed the numbers.  You know this clearly shows you to be wrong, so you have to "simplify" it to a point where you have constructed an example that breaks.  It's not the concept that is broken, just YOUR example. 

I can fix your example very easily.  First your typo has to be fixed.  "The 1.2kg balls that also move at 1m/s" should be "The 1.2kg balls that also move at 10 m/s", no? 

Then change the spacing of the balls from "1 m" to 0.1 meter.  Now the balls will hit the sails and the car will be propelled faster than the wind.

--- End quote ---

Thanks for correcting my typo. It is 10m/s as you correctly pointed out.

OK we can change the ball distance to 0.1m it will make no difference.
Now you have about 5 balls moving around between sails assuming they do not fall down.
The reason for simplification is so you understand that air is made from individual molecules. It is not a long stick pushing the vehicle as Derek falsely explained in his video.

The vehicle with wheels that Derek falsely claimed to be the equivalent of a direct downwind vehicle is actually the equivalent of a direct upwind vehicle with input wheels on the floor and output wheel traveled on the lumber.
Confusing input with output will result in ridiculous conclusions.

Back to latest example where wind speed is 5m/s and vehicle speed 10m/s in the same direction as the wind.
Will the vehicle/sails not hit the balls? no matter how small or spaced apart?
And vehicle hitting the balls is very different from balls hitting the vehicle. One case will slow down the vehicle and the other one will accelerate the vehicle.

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