humber: frames of reference are not being switched midstream. The essence is that the vehicle cannot tell the difference between being on a treadmill in still air, and rolling on the road at exactly the windspeed. Or for that matter being on a treadmill on top of a car driving downwind at windspeed, with the treadmill speed matched to the roadspeed.
Another example of why kinetic energy is relative: You are on a plane traveling at 200 m/s (relative to the earth surface) with a gun. Muzzle velocity also happens to be a nice subsonic 200 m/s. A sceptic is trying to kill you. Does it make a difference if you are shooting towards the front or the rear of the airplane?
Also: do you believe that iceboats are able to move with a downwind vector component that is greater than the windspeed?
// CyCrow
Not another one. Please. Take a look at the cart. Is it travelling? No.
Is there any wind. No
It is one thing to make a little toy, and make an error in understanding, but you seem to have gone ballistic, and I see this on other forums.
Has nothing I have said to you made any sense?
Oh, that's "normal" physics.
It has no kinetic energy, because it is essentially motionless. I have tried
explained to you that the only a tiny amount would ever be available.
If the system were to be perfect, then it would be zero. Not above windspeed, but at O speed. In a wind, it will stand still. Now your real cart will not do this, because what it does on the tfreadmill is entirely artificial!
It does not work like that at any speed!
You talk of all sorts of esoterica, but ignore the fact it doesn't accord with reality.
This is not a model of the cart, for two reasons;
1. It has nothing to do with being at windspeed
2. It is not an accurate model of your cart in any wind.
Let me disabuse you of one thing. The speed that you see is the speed that it is really traveling, and would travel if made.
You know what that would be ? A cart with its prop and drive shafts (almost) welded together, but it would waste more energy than that.
Think about it. Replace the belt with two drive wheels, like you see cars on a dynamo. Got it? The front and rear wheels are on, say, a pair of rollers.
What do you see, between the rollers? The floor. Is the cart moving relative to the floor? No. You are driving it so, it can standstill.
Don't say ...but the propellor.
No that is being driven BY the rollers. Not the other way !
Where is the wind? You can't mathematically subtract physical entities as if they were only vectors. You have been literal.
A vector is figurative.
