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

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gnuarm:
I made the drawing, not that it will make any difference.  ED seems to always find a bogus out that he will not back down from.  But for others, here it is.



The idea is simple.  Remove the propeller from the Blackbird which is hard to analyze because of the way it interacts with the wind.  Here simple sails are used, which fit EDs favorite equation perfectly. 

The pulley ratios make the belt move backwards relative to the car, at 3/4 of the speed of the car relative to the ground.  This means the sails move relative to the ground, at 1/4 the speed of the car relative to the ground.

So now, at any speed up to four times the speed of the wind, the sails will receive power according to the equation ED himself has provided.

The sails collapse on reaching the end of the belt, so they do not interact with the wind at all.  So ED's analysis using the "average" speed of the sails is totally bogus. 

This simply model and analysis is so clear, that even ED is having trouble finding enough toilet paper to clean up his BS in trying to explain why it won't work.  I'm surprised he hasn't tried to find energy storage in something. 

pcprogrammer:

--- Quote from: gnuarm on July 16, 2022, 04:26:42 pm ---This simply model and analysis is so clear, that even ED is having trouble finding enough toilet paper to clean up his BS in trying to explain why it won't work.  I'm surprised he hasn't tried to find energy storage in something.

--- End quote ---

Ooh I see it now, there is energy stored in the toilet paper. You can burn it to make steam :-DD

electrodacus:

--- Quote from: cbutlera on July 16, 2022, 10:00:19 am ---
That is a nice diagram, although there are some errors in the equations.

For the purposes of this thought experiment, the vehicle is assumed to be travelling at a constant velocity.  The question being asked is whether there is any net power remaining that could be used to accelerate the vehicle.

The first equation error is that FM should be equal to -FG.  The two forces must be of equal magnitude but opposite direction, if the vehicle is to remain at a constant velocity.

The second equation error is the inclusion of the Pin term in the equation for Pout.  The motor knows nothing about Pin other than the force FG that it has to compensate for.

The third equation error is the sign of Pnet.  The net power remaining is equal to the power provided by the generator, less the power consumed by the motor, not the other way around.

With these corrections, Pout will be negative in case A), the below wind speed case.  In other words the motor will be acting as a generator, as would be expected.

In case C), the above wind speed case, Pout will now be 4W.  So a power Pnet = 6W will remain and could be utilised to accelerate the vehicle.

--- End quote ---

The vehicle at the start of the experiment is not moving (for many people a moving vehicle is a difficult concept).
A moving vehicle will have stored kinetic energy.
What I calculate is the power at input vs power at the output.
For input force at the generator "G" wheel I just select a force so that generated power is 10W
This 10W is the applied to the motor wheel "M" so that vehicle can move from left to right.
To this 10W from input the Wind treadmill adds additional power in case A as vehicle speed is below wind speed and that additional power adds to the motor power.
The Pnet = Pout  - Pin  and this in case A is 20W meaning vehicle will accelerate from left to right at 20W rate.
So if you want to find out the speed of the vehicle after 1ms ideal case no friction
The you know vehicle is 10kg and you know applied power 20W and also know starting kinetic energy is zero.
After 0.001 seconds the 20W will convert in to 20mWs and that will be the new kinetic energy of the vehicle.
From that you can calculate the speed 0.020Ws = 0.5 * 10kg * v2
v = sqrt(0.020Ws/(10*0.5)) = 0.063m/s Direction of the vehicle will be left to right.

As I already mentioned the power from G wheel is transferred to M wheel  either mechanically through a belt or electrically through wires but ideal case is considered so power is transferred with zero loss.
The motor can not act as a generator due to vehicle design (blackbird even implemented a freewheel so only generator wheel can turn the propeller the propeller can not turn the wheels).

Are you saying that in case C vehicle can move from left to right ?

electrodacus:

--- Quote from: gnuarm on July 16, 2022, 04:26:42 pm ---I made the drawing, not that it will make any difference.  ED seems to always find a bogus out that he will not back down from.  But for others, here it is.


The idea is simple.  Remove the propeller from the Blackbird which is hard to analyze because of the way it interacts with the wind.  Here simple sails are used, which fit EDs favorite equation perfectly. 

The pulley ratios make the belt move backwards relative to the car, at 3/4 of the speed of the car relative to the ground.  This means the sails move relative to the ground, at 1/4 the speed of the car relative to the ground.

So now, at any speed up to four times the speed of the wind, the sails will receive power according to the equation ED himself has provided.

The sails collapse on reaching the end of the belt, so they do not interact with the wind at all.  So ED's analysis using the "average" speed of the sails is totally bogus. 

This simply model and analysis is so clear, that even ED is having trouble finding enough toilet paper to clean up his BS in trying to explain why it won't work.  I'm surprised he hasn't tried to find energy storage in something.

--- End quote ---

I appreciate the fact the you took the time to draw this.
Let say both wind speed and vehicle speed is 10m/s

So even with this drawing you can not see that sails travel at the same speed as the vehicle ?
The sail rotates around the vehicle (just take any individual sail) it will travel at 2.5m/s relative to ground when sail is unfolded above the vehicle and then travel at 17.5m/s relative to ground when below the vehicle.
Average of this two speeds show that sail travels with the vehicle at 10m/s and it rotates around the vehicle at 7.5m/s

Let me know if any of this speed values I mentioned are wrong and if so what is the value.

gnuarm:

--- Quote from: electrodacus on July 16, 2022, 05:03:31 pm ---
--- Quote from: gnuarm on July 16, 2022, 04:26:42 pm ---I made the drawing, not that it will make any difference.  ED seems to always find a bogus out that he will not back down from.  But for others, here it is.


The idea is simple.  Remove the propeller from the Blackbird which is hard to analyze because of the way it interacts with the wind.  Here simple sails are used, which fit EDs favorite equation perfectly. 

The pulley ratios make the belt move backwards relative to the car, at 3/4 of the speed of the car relative to the ground.  This means the sails move relative to the ground, at 1/4 the speed of the car relative to the ground.

So now, at any speed up to four times the speed of the wind, the sails will receive power according to the equation ED himself has provided.

The sails collapse on reaching the end of the belt, so they do not interact with the wind at all.  So ED's analysis using the "average" speed of the sails is totally bogus. 

This simply model and analysis is so clear, that even ED is having trouble finding enough toilet paper to clean up his BS in trying to explain why it won't work.  I'm surprised he hasn't tried to find energy storage in something.

--- End quote ---

I appreciate the fact the you took the time to draw this.
Let say both wind speed and vehicle speed is 10m/s

So even with this drawing you can not see that sails travel at the same speed as the vehicle ?
The sail rotates around the vehicle (just take any individual sail) it will travel at 2.5m/s relative to ground when sail is unfolded above the vehicle and then travel at 17.5m/s relative to ground when below the vehicle.
Average of this two speeds show that sail travels with the vehicle at 10m/s and it rotates around the vehicle at 7.5m/s

Let me know if any of this speed values I mentioned are wrong and if so what is the value.

--- End quote ---

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. 

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