Yes SD, but wheelslip was not mentioned until I raised it. When I did, it was incorrectly applied to the treadmill and cart. In the case of Goodman's cart, it may well be of use.
Wheel slip was not mentioned until you mentioned it. When you did, you incorrectly applied it to the treadmill and cart. You still are doing so now.
There's a stream in Wales that contradicts that. The water runs like a sheet over a flat, hard sedimentary bed. There is no pooling.
Just your definition of what is possible. Second hand assumptions. None relevant to the point about the speed of objects in steady flow.
All these examples do, is illustrate how variable conditions really are, and how far you are given to circumlocution.
Again, as per example of wheel slip above, no-one mentioned water going uphill until you introduced it as a way to confuse the issue of the speed of objects in fluid flow. Now you have managed to develop yet one more line of argument, which you now chuck in other people's faces as being irrelevant.
I was thinking though, about that stream. Well, your are right, I can't provide a reference, but I was wondering if I proposed a situation where a river may behave as I said, would you be able to help me clear up any mistakes that I may make?
When I read this I warmed to you. At last humber is showing some readiness to listen and learn, some basic communication skills, some humility. If that's the case, I congratulate you on your progress. If, however, as I then began to suspect, you are just being sarcastic...well, let's forget that (thanks for the reminder Gaspode) and deal with the text as if you were genuinely asking for help...
That's a bit hard I think, so perhaps you can help me with a simpler problem.
I put a rock in the river, and it did not travel at waterspeed as expected.
I realised that perhaps only buoyant objects may do this. Yes, of course. I exclaimed. But then I began to wonder if the transition from river bed to waterspeed may not be sudden. If the object were a little buoyant, may it not be simply dragged slowly along the bed? If it floated, say, 1cm above the bed would that mean it would suddenly jump to waterspeed?
Then I noticed something else. It appears that different objects, even though they are they same height above the bed, seem to travel at different speeds.
This makes me doubt that all objects get to waterspeed, even if time were allowed for acceleration. What do you think?
You see, even if you started off with a mind set on sarcasm, you are presumably presenting things the way you see them, and I am afraid I have to say that your understanding of fluid flow, even bits of muck in a stream, is very poor. Your basic point is right (which I will elaborate here), that a heavy rock will be pressed to the stream bed by its weight, and thus the friction between it and the bed may overcome the DRAG FORCE of the water flowing past. Indeed, heavy rocks can be shoved and rolled and bounced down a river, since the flow is not of a constant speed, depth, etc.
Considering however a single bit of a river in a steady rate of flow (but in a real river, where there are eddies and so on), we will find that lighter particles are lifted by eddies more often and bumped and dragged by the water more often. Much lighter particles still will hardly impact anything, and will flow at the speed of the water around them - roughly, because that will be turbulent.
If we now imagine a flow (unusual in nature, if possible at all) where there are no eddies, so particles are either too heavy to float or are light enough to be suspended, then we may still see the phenomenon that you describe - particles nearer the bottom may be going slower than those higher up (or further from the sides). That is simply because the water is impeded by friction at the bottom and sides, and we get that gradual differential in speed of flow from boundaries towards the middle, where the water flows fastest. Hence, if you observe suspended particles moving at different speeds depending on height, that is because they are suspended in fluid that is moving at different speeds, the same speed they are moving at, the condition we have all described to you, where the relative velocity between the object and fluid is zero, and there is therefore no resultant drag forces applied to accelerate (change the velocity of) the object or the fluid around it.
So, if you were genuinely looking for help understanding that, or if you were presenting it as another sarcastic objection to what is orthodox physics, there is my reply. If you see anything wrong with it, you are free to say what that is. Please avoid mixing up conditions in the scenarios you present. You must discuss what will happen to an object in ideal conditions, or when there are eddies, or when there are no eddies but a gradient of fluid speeds, etc. That kind of thing may have led to some of your confusions.
A further point in passing regarding your confusion about bow-waves and drag in these situations. ETA:
There is the 'downwind' drag, propelling the balloon, but there is also the opposing drag of the balloon through the air. It's not a free ride
When we imagine the scenario prior to steady state, when a balloon or boat, etc. is being accelerated, as I have said before, we need only consider the drag force applied to it accelerating it towards the velocity of the flow. I have asked for any others you think apply and you have so far failed to tell me what there might be. When there is that relative speed, fluid flowing past the object, there is a higher pressure behind the object (I'm using 'behind' and 'in front' as related to the direction of flow), which is like the bow wave. It pushes. The same flow tends to cause eddies and a low pressure in front of the body, like a wake, which we can only think of as pulling the object, not as retarding it. Thus there is just the 'drag' force, however you divide it up. Indeed whether there is such a thing as a pull force is debatable, and usually we think only of the low pressure in relation to its opposite on the other side, pushing, just as we don't consider 'cold' as a thing, only as a lower heat condition.
Of course, these directions seem odd (bow waves are usually in front of things like boats and wakes behind), but that is because we are not considering an object moved by a separate motive force (like a body falling or a powered boat on a still lake), which is why I raised the warning about using those scenarios and the term 'terminal velocity'.
I hope you will see that all of the above statements are consistent, not only with each other, but with the correct translations into other inertial frames of reference - such as, indeed, when a powerboat switches off its motor and comes to match the speed of the stationary lake it has been powering across.
If you would genuinely apply yourself to answering my question - what is that missing force - or to square your rendition of the situation with Newton, I think you will give yourself the help you have asked for. ETA: You would discover, and/or admit, that in the relevant scenario, there is no other force of impedance; there is indeed a 'free ride'.
