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Newton's third law problem.

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IanB:

--- Quote from: electrodacus on November 25, 2022, 04:50:11 am ---It could fly if the friction is high enough or the acceleration rate of the treadmill is large enough.
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Don't be absurd.


--- Quote ---The point is the body is floating.
--- End quote ---

No, the point is that it is fixed on a horizontal plane and is not free to rotate.


--- Quote ---
--- Quote from: IanB on November 25, 2022, 04:42:10 am ---There is no law of physics that says this.

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It is for this particular gearbox configuration as it is locked basically no different from a rock


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Saying that it is locked is a conclusion reached before doing the analysis. It is clearly not locked, since it has all sorts of axles and freely rotating wheels and belts. It would only be locked if it had brakes, and there are no brakes in the model. The wheels are free to turn.


--- Quote ---
--- Quote from: IanB on November 25, 2022, 04:42:10 am ---Just like car's gearbox then? It has the input connected to the engine, the output to the road, and the body not connected to anything? And yet, somehow, the gearbox in a car works.

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The car gearbox body is connected to the motor stator or engine body.
It is like the treadmill body was connected to this vehicle body instead of the ground.

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This is meaningless. No clue what you are trying to say.

Anyway, good night. We will see tomorrow if anybody else feels like playing with the troll.

electrodacus:

--- Quote from: IanB on November 25, 2022, 05:23:16 am ---Don't be absurd.

No, the point is that it is fixed on a horizontal plane and is not free to rotate.

Saying that it is locked is a conclusion reached before doing the analysis. It is clearly not locked, since it has all sorts of axles and freely rotating wheels and belts. It would only be locked if it had brakes, and there are no brakes in the model. The wheels are free to turn.

This is meaningless. No clue what you are trying to say.

Anyway, good night. We will see tomorrow if anybody else feels like playing with the troll.

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You mentioned forces come in pairs.
The only force pair is F1 relative to ground not relative to vehicle body.
So vehicle/gearbox has input connected to F1 and output to ground and nothing else.

I should have insisted more on the floating gearbox as it seems it was not obvious.

PlainName:

--- Quote from: IanB ---Anyway, good night. We will see tomorrow if anybody else feels like playing with the troll
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I admire your perseverance and composure in the face of insurmountable odds  :-+

electrodacus:

--- Quote from: IanB on November 25, 2022, 05:23:16 am ---Don't be absurd.


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Here a link to a proper vehicle physics calculator https://www.electromotive.eu/?page_id=12&lang=en
Just change the head wind to 100km/h leave all the rest as default (it is for an ebike) see what power is needed for the biker pedaling at 20km/h in a 100km/h headwind and is almost 20kW as they use the proper equation.

Circlotron:

--- Quote from: electrodacus on November 27, 2022, 01:33:08 am ---Here a link to a proper vehicle physics calculator https://www.electromotive.eu/?page_id=12&lang=en

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That calculator is next to useless. It has no facility to include coefficient of drag so it doesn't know the difference between a teardrop shape and a box shape.

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