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

[electrodacus]

Nah there's plenty of energy available in wind. You know, 1/2*m*v^2 is rarely equal to 0.

You get that the air molecules can no longer hit the vehicle when both the vehicle and air molecules have the same speed in the same direction.
Even your wrong wind power equation agrees with that statement.
But since you think over 100% efficiency is possible and think that you get more propulsion power than braking power at the wheels is hard to have a rational discussion.
Until you recognise that above 100% efficiency is not possible. I'm just wasting my time.

Do you think a propeller in still air can't work? Lol.
Okay let's wrongly assume there is a problem at this speed. Then when the car goes at twice the wind speed, there's plenty of air for the prop.

Ever heard about heat pumps? They can have 300% efficiency.
If you want to understand why, and how, then you'll have to learn about thermodynamics.

Where have I said anything about a "propeller in still air" whatever you think that means.
 When vehicle is at 2x the wind speed directly downwind the propeller (part of the vehicle) hits the air molecules not the other way around if you ignore the pressure differential stored energy.
So if you see the air as 1.2kg balls 1m apart traveling at say 10m/s and a vehicle traveling at 20m/s will bump in to the balls slowing down the vehicle not accelerating the vehicle.

A heat pump is what the name implies a pump. It is incorrect to say it is 300% efficient the correct term will be it has a COP (coefficient of performance) of 3.
You have to learn more than just thermodynamics but that will be a good start  so you can stop with the 300% efficiency nonsense.

[electrodacus]

The prop is geared to the wheels. If the wheels turn, the prop turns.
And if the prop turns, the kinetic energy of the wind behind the car is reduced, which means you get energy to the car. Very simple.

Yes ideal case wheels turn and propeller turns and there is no acceleration as power you put out at the propeller can only be ideal case equal with braking power at the wheels.
But you will not going to get the above as you think above 100% efficiency is possible so until you get that is false we will have a circular conversation.

[PlainName]

You get that the prop thrust is actually moving backwards from the vehicle, so presenting resistance to the wind which is at vehicle speed?

Ah, forgot, no you don't. In your universe the turning prop doesn't produce thrust of any kind in any direction.

You forget that the prop is powered by wind power so if wind power is zero prop power is zero.

What part of "turning prop" don't you understand? It doesn't matter where the power comes from, if the prop is turning it's producing thrust. And in EVERY demo we've seen, the prop is turning. It is thus producing thrust.

Are you denying that?
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[Naej]

The prop is geared to the wheels. If the wheels turn, the prop turns.
And if the prop turns, the kinetic energy of the wind behind the car is reduced, which means you get energy to the car. Very simple.

Yes ideal case wheels turn and propeller turns and there is no acceleration as power you put out at the propeller can only be ideal case equal with braking power at the wheels.
But you will not going to get the above as you think above 100% efficiency is possible so until you get that is false we will have a circular conversation.

Ok let's assume that the efficiency, defined as the ratio between the power of the prop and the wind power (1/2*area*density*wind speed^2*car speed), is 50%.
Can you guess the maximal speed?

the propeller (part of the vehicle) hits the air molecules not the other way around

I think before telling people they should learn physics, you should learn relativity. At least the galilean one 

[electrodacus]

What part of "turning prop" don't you understand? It doesn't matter where the power comes from, if the prop is turning it's producing thrust. And in EVERY demo we've seen, the prop is turning. It is thus producing thrust.

Are you denying that?

Say propeller produces 100W of thrust.
How much power do wheels need to deliver to an ideal propeller for that 100W worth of thrust ?
If you say 100W then you are correct so your propeller pushes with 100W and your wheels are braking with 100W so what will be the net of that ?
100W-100W=0W

[Naej]

What part of "turning prop" don't you understand? It doesn't matter where the power comes from, if the prop is turning it's producing thrust. And in EVERY demo we've seen, the prop is turning. It is thus producing thrust.

Are you denying that?

Say propeller produces 100W of thrust.
How much power do wheels need to deliver to an ideal propeller for that 100W worth of thrust ?
If you say 100W then you are correct so your propeller pushes with 100W and your wheels are braking with 100W so what will be the net of that ?
100W-100W=0W

I say 30W coming from the gear and 1000W from the wind, at twice the wind speed.

[electrodacus]

Ok let's assume that the efficiency, defined as the ratio between the power of the prop and the wind power (1/2*area*density*wind speed^2*car speed), is 50%.
Can you guess the maximal speed?

Efficiency will not be defined as those two quantities.

Input is wind power and nothing else.
Output = Input - friction losses.

Ideal case you have no friction loss and so 100% of input power is converted into kinetic energy.

[electrodacus]

I say 30W coming from the gear and 1000W from the wind, at twice the wind speed.

If vehicle is at 2x the wind speed directly downwind you will refer to that wind power as -1000W  (yes negative) meaning it will slow down the vehicle.
As input there can not be anything else other than wind power and what you fail to accept power from stored energy

[Naej]

I say 30W coming from the gear and 1000W from the wind, at twice the wind speed.

If vehicle is at 2x the wind speed directly downwind you will refer to that wind power as -1000W  (yes negative) meaning it will slow down the vehicle.
As input there can not be anything else other than wind power and what you fail to accept power from stored energy

No a propeller gives thrust, unless the blade angle is incorrect.
If you insist with -1000W, with an output of 400W you'll have an efficiency of -40%.
It's pretty silly, but if you are amused by it, why not.

[electrodacus]

No a propeller gives thrust, unless the blade angle is incorrect.
If you insist with -1000W, with an output of 400W you'll have an efficiency of -40%.
It's pretty silly, but if you are amused by it, why not.

Do you have a problem considering the vehicle powered by 1.2kg balls spaced 1m apart ? say balls travel at 10m/s
You are in your vehicle no matter the design as long as you have no energy source on board and you will not use your mussels to power the vehicle.
Do you think this ball powered vehicle you find yourself in can exceed the speed of the balls ?

-when you are stationary you get the most power as 10 balls will hit your vehicle very second.
-when vehicle is at 5m/s only 5 balls will hit the vehicle very second and relative to vehicle the balls will only be at 5m/s so less balls hitting the vehicle softer.
-when vehicle is at 10m/s (say no friction and you got there) no balls can hit your vehicle so no ball power.
But say someone pushes you to 20m/s
-will your vehicle not hit now 10 balls each second at 10m/s so your vehicle will be slowed down?

If you think a non compressible fluid is different from this balls explain how.

[Naej]

No a propeller gives thrust, unless the blade angle is incorrect.
If you insist with -1000W, with an output of 400W you'll have an efficiency of -40%.
It's pretty silly, but if you are amused by it, why not.

Do you have a problem considering the vehicle powered by 1.2kg balls spaced 1m apart ? say balls travel at 10m/s
You are in your vehicle no matter the design as long as you have no energy source on board and you will not use your mussels to power the vehicle.
Do you think this ball powered vehicle you find yourself in can exceed the speed of the balls ?

-when you are stationary you get the most power as 10 balls will hit your vehicle very second.
-when vehicle is at 5m/s only 5 balls will hit the vehicle very second and relative to vehicle the balls will only be at 5m/s so less balls hitting the vehicle softer.
-when vehicle is at 10m/s (say no friction and you got there) no balls can hit your vehicle so no ball power.
But say someone pushes you to 20m/s
-will your vehicle not hit now 10 balls each second at 10m/s so your vehicle will be slowed down?

If you think a non compressible fluid is different from this balls explain how.

You are correct in that with a sail you can't go faster than the wind.
The solution here is to use gears with the wheels to a bat, and the bat hits the balls and accelerate them by 10m/s for example.
So before the car they have 1/2*m*10²  in kinetic energy and after they have 0. Can you guess where the kinetic energy went?

[PlainName]

What part of "turning prop" don't you understand? It doesn't matter where the power comes from, if the prop is turning it's producing thrust. And in EVERY demo we've seen, the prop is turning. It is thus producing thrust.

Are you denying that?

Say propeller produces 100W of thrust.
How much power do wheels need to deliver to an ideal propeller for that 100W worth of thrust ?

Completely irrelevant. Either it is producing thrust - small, large, whatever - or it is not. You can argue about how much and where the power is coming from later.

So, are you saying a turning prop is not producing thrust?

[electrodacus]

You are correct in that with a sail you can't go faster than the wind.
The solution here is to use gears with the wheels to a bat, and the bat hits the balls and accelerate them by 10m/s for example.
So before the car they have 1/2*m*10²  in kinetic energy and after they have 0. Can you guess where the kinetic energy went?

You can go faster than wind with a sail vehicle if you add energy storage so take energy from the wheel store in a battery or flywheel and use that to exceed wind speed.
The amount you gain by hitting the ball will be using at the wheel to brake the vehicle so you gain nothing.
The problem is you thinking you can get more from the bat compared to what you stole at the wheel but that is never the case in this universe.

If your vehicle is at 20m/s and vehicle mass is say 300kg then vehicle kinetic energy is 0.5 * 300 * 20² = 60000Ws
Now you apply say a brake of 10N for a fraction of a second say 0.001s that will get you 100N * 20m/s * 0.001s = 2Ws
So the vehicle is now at just 59998Ws (lower speed)
And you take this 2Ws you got from the wheels and put it in a 100% efficient bat then what will happen is you best case put those stollen 2Ws back and you are now back from where you started at 60000Ws so same speed as it is the ideal case.
Do you understand how useless it will be to have a bat connected to wheels when vehicle is powered by balls ?

[electrodacus]

Completely irrelevant. Either it is producing thrust - small, large, whatever - or it is not. You can argue about how much and where the power is coming from later.

So, are you saying a turning prop is not producing thrust?

Actually highly relevant.
The propeller produces thrust but the energy it took from the wheels produced what you can call anti-thrust.
As when you take energy at the wheel you apply brakes to vehicle.

The only reason this even makes any sense (having propeller conned to wheels) is because it can be used as an energy storage device due to air being a compressible fluid.
So when vehicle starts it may be more like 100W taken at the wheels and propeller 70% efficient  60W go to storage 10W is thrust and 30W lost as heat due to propeller and gear inefficiency.
That accumulated stored energy over time will take over the propulsion and allow vehicle to get well above wind speed for some limited amount of time.

[Naej]

And you take this 2Ws you got from the wheels and put it in a 100% efficient bat then what will happen is you best case put those stollen 2Ws back and you are now back from where you started at 3000Ws so same speed as it is the ideal case.
Do you understand how useless it will be to have a bat connected to wheels when vehicle is powered by balls ?

You forgot about the balls and their energy. 

[electrodacus]

You forgot about the balls and their energy. 

I did not. You forgot that energy is useful to you when they move in the direction you want to move.
So their energy is useful to direct downwind vehicle only  when vehicle moves slower than the balls. When vehicle moves faster it is counterproductive unless what you want is to slow down. 

[Naej]

You forgot about the balls and their energy. 

I did not. You forgot that energy is useful to you when they move in the direction you want to move.
So their energy is useful to direct downwind vehicle only  when vehicle moves slower than the balls. When vehicle moves faster it is counterproductive unless what you want is to slow down.

I'm sorry where did you see in the first principle of thermodynamics that you should only count energy moving in some direction?
I can't see it 

So let's say your ball has a mass of one ton, moving at 10 m/s. There is a collision with a bat, with 2J of energy (your number).
Compute the recoil, i.e. the momentum change of the bat.

[electrodacus]

I'm sorry where did you see in the first principle of thermodynamics that you should only count energy moving in some direction?
I can't see it 

So let's say your ball has a mass of one ton, moving at 10 m/s. There is a collision with a bat, with 2J of energy (your number).
Compute the recoil, i.e. the momentum change of the bat.

I do not think I asked you about aphantasia.

Can you visualize the difference between when the ball moves in the direction of travel and when it moves in the opposite direction ?
If you are in that vehicle looking out at balls traveling at 10m/s
when vehicle is at 5m/s you will see balls coming from the back of your vehicle and moving past your vehicle at around 5m/s so all you need to do is still the bat out and the ball will hit it providing you with energy to increase vehicle speed.
When vehicle is at 15m/s then you see balls moving in the opposite direction so come from the front of your vehicle and move backward so if you stick out the bat and ball hits it it will slow your vehicle down.
You will need to prepare to swing that bat at high speed to heat that vehicle after it just passed the vehicle and so you need quite some energy to hit that ball in order to accelerate your vehicle. So much energy that even at 100% efficiency it will be barely equal with the amount of energy you lost by braking the vehicle.

Hope you can see the difference between a ball coming from the back of the vehicle at 5m/s and one coming from the front of vehicle at 5m/s
They both have equal speed and mass but the direction of travel is different thus one is positive and the other is negative. One can accelerate the vehicle and the other can slow down the vehicle by the same amount.

[Naej]

I'm sorry where did you see in the first principle of thermodynamics that you should only count energy moving in some direction?
I can't see it 

So let's say your ball has a mass of one ton, moving at 10 m/s. There is a collision with a bat, with 2J of energy (your number).
Compute the recoil, i.e. the momentum change of the bat.

I do not think I asked you about aphantasia.

Can you visualize the difference between when the ball moves in the direction of travel and when it moves in the opposite direction ?
If you are in that vehicle looking out at balls traveling at 10m/s
when vehicle is at 5m/s you will see balls coming from the back of your vehicle and moving past your vehicle at around 5m/s so all you need to do is still the bat out and the ball will hit it providing you with energy to increase vehicle speed.
When vehicle is at 15m/s then you see balls moving in the opposite direction so come from the front of your vehicle and move backward so if you stick out the bat and ball hits it it will slow your vehicle down.
You will need to prepare to swing that bat at high speed to heat that vehicle after it just passed the vehicle and so you need quite some energy to hit that ball in order to accelerate your vehicle. So much energy that even at 100% efficiency it will be barely equal with the amount of energy you lost by braking the vehicle.

Hope you can see the difference between a ball coming from the back of the vehicle at 5m/s and one coming from the front of vehicle at 5m/s
They both have equal speed and mass but the direction of travel is different thus one is positive and the other is negative. One can accelerate the vehicle and the other can slow down the vehicle by the same amount.

Yes the ball is coming from the front of the vehicle.
And you accelerate it with your bat. Because you use recoil.
Now compute the recoil with a 2J bat and a 1t ball.
It's easy, just use the conservation of momentum.

[electrodacus]

Yes the ball is coming from the front of the vehicle.
And you accelerate it with your bat. Because you use recoil.
Now compute the recoil with a 2J bat and a 1t ball.

OK, I guess we can get closer.
The bat weight means nothing as it is part of the vehicle total weight.
The 2J is energy I like to refer to it as 2Ws (2 Watt for one second or 1W for 2 seconds or any other combination).
In order to supply your batt with 2J you need to take 2J at the wheel and that will be subtracted from the vehicle kinetic energy meaning vehicle will have slightly lower speed after you take those 2J at the wheel.

So 2J is all you get best case (ideal) in terms of propulsion from your bat.

[Naej]

Yes the ball is coming from the front of the vehicle.
And you accelerate it with your bat. Because you use recoil.
Now compute the recoil with a 2J bat and a 1t ball.

OK, I guess we can get closer.
The bat weight means nothing as it is part of the vehicle total weight.
The 2J is energy I like to refer to it as 2Ws (2 Watt for one second or 1W for 2 seconds or any other combination).
In order to supply your batt with 2J you need to take 2J at the wheel and that will be subtracted from the vehicle kinetic energy meaning vehicle will have slightly lower speed after you take those 2J at the wheel.

So 2J is all you get best case (ideal) in terms of propulsion from your bat.

I didn't ask what you wrongly believe to be the best case, I asked exactly what will happen.
A 2 "Ws" bat collides with a 1t ball, what is the recoil?

There may be a solution here: https://en.wikipedia.org/wiki/Elastic_collision#One-dimensional_Newtonian

[electrodacus]

I didn't ask the best case, I asked exactly what will happen.
A 2 "Ws" bat collides with a 1t ball, what is the recoil?

You care what happens with the car not with the ball.
If all you have to spend is 2Ws then all you get best case is 2Ws worth of propulsion.
You can apply that 2Ws to the wheel pushing against the ground or to the batt pushing against the ball is same thing in ideal case. In real world is better to apply to wheel as is more efficient.

[Naej]

I didn't ask the best case, I asked exactly what will happen.
A 2 "Ws" bat collides with a 1t ball, what is the recoil?

You care what happens with the car not with the ball.
If all you have to spend is 2Ws then all you get best case is 2Ws worth of propulsion.
You can apply that 2Ws to the wheel pushing against the ground or to the batt pushing against the ball is same thing in ideal case. In real world is better to apply to wheel as is more efficient.

I asked the recoil on the bat.
You can compute it with these formulae: https://en.wikipedia.org/wiki/Elastic_collision#One-dimensional_Newtonian
Are you afraid to compute it in case it will lead to more than 2Ws? (coefficient of performance>1)

[electrodacus]

I asked the recoil on the bat.
You can compute it with these formulae: https://en.wikipedia.org/wiki/Elastic_collision#One-dimensional_Newtonian
Are you afraid to compute it in case it will lead to more than 2Ws? (coefficient of performance>1)

Fine I will waste more of my time most likely.

Vehicle was 300kg driving at 20m/s relative to ground through a space filled with balls traveling in the same direction at just 10m/s
Starting vehicle kinetic energy 0.5 * 300kg * 20m/s² = 60000Ws 
We take 2Ws from the wheel so 60000Ws - 2Ws = 59998Ws
New vehicle speed sqrt(59998 / (300 * 0.5)) = 19.9996666m/s
Bat now has the 2Ws available to hit a ball you mentioned 1000kg ball but it makes no difference for the vehicle as you will see
When the bat hits the ball it will take 2Ws from the ball kinetic energy and transfer to vehicle (ideal case).
The ball was moving at 10m/s relative to the ground so it had
0.5 * 1000 * 10² = 50000Ws
Will have 2Ws less after the hit so you can calculate how much lower the speed will be relative to the ground (not much as is a hughe 1000kg ball).
The vehicle again ideal case will gain thoe 2Ws so will be back at 60000Ws and so back to 20m/s
 

 

[PlainName]

Completely irrelevant. Either it is producing thrust - small, large, whatever - or it is not. You can argue about how much and where the power is coming from later.

So, are you saying a turning prop is not producing thrust?

Actually highly relevant.
The propeller produces thrust but the energy it took from the wheels produced what you can call anti-thrust.

What is anti-thrust? Is it blowing the wrong way or what? No, forget that - that's just another dead cat you're playing.

You can argue where and how the power is stolen some other message. We don't care if the vehicle is speeding up, down, sideways or outside the wire, but just this once please answer this single thing.

You agree that the turning prop, HOWEVER IT'S POWERED, is producing thrust in the rearward direction?