How Electricity Actually Works

On another controversial claim seen in a YouTube video, the notion that you can make a wind powered car that can go down wind faster than the wind still messes with my head.

My understanding is there are two effective forces, one is the wind pushing, but the other, less obvious, is the wind "pulling"  (though still pushing). Sail boats can also go much faster than the wind.

I didn't spend a lot of time looking at this, but appears to be Bernoulli force, just like an airplane. The wind travels faster over the sail, which causes low pressure, so you have additional force acting on the sail which makes the boat go faster.

In the ground car, the low pressure is created by the propeller. The wind does not spin the propeller, it moves the car whose wheels are connected to the propeller causing it to spin.

czarivey

4,837 posts

05-02-2022 at 11:37am

@jea48

In all of the books of electronics and electrical engineering, the electric signal through the conductor is the ordered motion of electrons

@czarivey

This guy wrote a few books too...

Here’s an article he wrote a few years ago.

What is Electronics - Ralph Morrison

Here is an excerpt from the article:

Storing or moving energy.

There is a common misconception that signals are carried in conductors. Somehow this association crosses over to the idea that conductors carry both signals and energy. A few simple calculations can show that this is a false idea. Consider a 50-ohm transmission line carrying a 5-volt logic signal. The initial current at switch closure is 500 mA. A typical trace is a a gram-mole of copper that has 6 x 10²³ copper atoms (Avogadro’s number). Each atom can contribute one electron to current flow. Knowing the charge on an electron makes it easy to show that the average electron velocity for 500 mA is a few centimeters per second. What is even more interesting is that only a trillion electrons are involved in this current flow. This means that only one electron in a trillion carries the current. This also says that the magnetic field that moves energy is not located in the conductors. The only explanation that makes sense is that energy in the magnetic field must be located in the space between two conductors. Conductors end up directing energy flow - not carrying the energy.

Here is another article written by the Late Ralph Morrison:

As for going faster than the wind...this is another one that academicians love to state purposely vaguely to make you think they are cleverer than they are.  Your vector downwind can never be faster than the wind.  In fact it must be quite a bit less  than the wind. but if you go at a 45 degree angle to the wind, your forward velocith is 1.414 x your wind vector velocity.  So in a 12 mph wind with a 10mph velocity in the windward direction, your forward velocith with be 14.14 mph.  No there is not special bernouli equation that causes you to go faster than the wind, just like the lighting of the lightbult, even just a little bit, cannot happen faster than the speed of light.   --Jerry

@carlsbad 

Are you seriously telling scientists who have researched this, modelled it, simulated it, and know all the forces in detail of how this works, that they are wrong?

The "car" they made goes in exactly the same direction as the wind and goes 2.5 times faster than the wind. They are going down-wind at 2.5 times the wind speed.

The bernoulli forces are similar to a plane. Faster moving air is lower pressure. They create a low pressure so that the air on the opposite side pushes towards the low pressure area.

@deludedaudiophile Well, I’m a physicist so no, I’m not saying physicists are wrong. I’ll saying that some laypeople trying to understand physics haven’t gotten it yet.

BTW, I do know bernoulli’s equation. It is what makes a plane fly, it isn’t a magic equation that causes a sail to push the winds.

Good luck. Hope you find that physics teaching gig you’re looking for.

Jerry

PS  Here is another physics demonstration you should appreciate, a ramp that shoots a ball higher than the ball was at the start.