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Newton's third law problem.
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IanB:

--- Quote from: electrodacus on November 25, 2022, 03:31:06 am ---Static analysis is the important part here. Vehicle is stationary to start so you need a higher F2 if you want to accelerate the vehicle to the right.
What helps you have a higher F2 is both energy storage in the rubber belt and stick slip hysteresis as shown clearly in the slow motion video.

--- End quote ---

Firstly, there is no rubber belt and no stick slip hysteresis because this is a CAD model. It does not contain those elements.

Secondly, no such invention is needed. If you move the treadmill, then by necessity the wheel on the treadmill will turn, and the belt will move, and the other wheel will turn, and the cart will move.
IanB:

--- Quote from: electrodacus on November 25, 2022, 03:37:37 am ---Can you be more specific ? Where there 3 points of contact for the gearbox ?
--- End quote ---

The axles (or bearings), the input shaft and the output shaft.


--- Quote ---Like I mentioned a gearbox with floating body is not actually a gearbox.
--- End quote ---

But it is not actually floating. When the input shaft rotates the gearbox is not free to rotate with it, it is fixed to the body of the cart. It would only be a floating gearbox if it was free to rotate with the input shaft.


--- Quote ---Force at the tape is irrelevant as that represents the belt and the only points making contacts are the two handles one is the input the other the output with the floating body and non relevant internal mechanism because the body is floating.

--- End quote ---

Not at all irrelevant, because forces come in pairs (Newton's 3rd law: every force has an equal and opposite reaction). In the same way that there is no such thing as a voltage at a single point (a voltage is always a difference between two points), there is no such thing as a force at a single point. There is always a reacting force paired with it. So the force pair on the handle of the scissors is like the input voltage on the primary of a transformer, and the force pair on the blades of the scissors is like the output voltage on the secondary of the transformer. Bear in mind that a transformer can often be floating; it does not have to be grounded at all.
electrodacus:

--- Quote from: IanB on November 25, 2022, 03:47:06 am ---
Firstly, there is no rubber belt and no stick slip hysteresis because this is a CAD model. It does not contain those elements.

Secondly, no such invention is needed. If you move the treadmill, then by necessity the wheel on the treadmill will turn, and the belt will move, and the other wheel will turn, and the cart will move.

--- End quote ---

Exactly. Since the diagram makes no mention about belt or any other part being elastic and since slip is also not mentioned then this diagram as a problem will  represent a system that can not move as F2 can not be larger than F1 no matter how large the F1 is the system will not move.
IanB:

--- Quote from: electrodacus on November 25, 2022, 03:56:06 am ---Exactly. Since the diagram makes no mention about belt or any other part being elastic and since slip is also not mentioned then this diagram as a problem will  represent a system that can not move as F2 can not be larger than F1 no matter how large the F1 is the system will not move.

--- End quote ---

This is faulty reasoning. The movement of the cart has nothing to do with the size of F2 and F1. They don't affect the analysis.
electrodacus:

--- Quote from: IanB on November 25, 2022, 03:56:00 am ---The axles (or bearings), the input shaft and the output shaft.

--- End quote ---

The input shaft is connected to treadmill and the output shaft to ground.
That is all the rest represent the gearbox body that is not connected to anything.


--- Quote from: IanB on November 25, 2022, 03:56:00 am ---But it is not actually floating. When the input shaft rotates the gearbox is not free to rotate with it, it is fixed to the body of the cart. It would only be a floating gearbox if it was free to rotate with the input shaft.

--- End quote ---

The gearbox body is not connected to anything so it is free to rotate with the input shaft if there is enough friction in the front wheel bearing.



--- Quote from: IanB on November 25, 2022, 03:56:00 am ---Not at all irrelevant, because forces come in pairs (Newton's 3rd law: every force has an equal and opposite reaction). In the same way that there is no such thing as a voltage at a single point (a voltage is always a difference between two points), there is no such thing as a force at a single point. There is always a reacting force paired with it. So the force pair on the handle of the scissors is like the input voltage on the primary of a transformer, and the force pair on the blades of the scissors is like the output voltage on the secondary of the transformer. Bear in mind that a transformer can often be floating; it does not have to be grounded at all.

--- End quote ---

Not quite sure the analogy works.
But an electronic component with just two connections will have the same current at input and output.

So F1 is the equal and opposite force in this setup and so they will always be equal unless energy storage and stick slip hysteresis or some similar trigger for charge discharge exist.
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