I want to know if moving along a vertical plane in a circle differs in its effects on the human body from moving horizontally in a circle. Imagine a ferris wheel with a diameter of 50 metres. If a person on it was travelling at 10miles an hours, would they get less dizzy than a person travelling on a roundabout or carousel with a diameter of 50 metres travelling at 10mph?
The inner part of your ear contains fluids that controls how dizzy you feel, with no consideration for direction. I believe astronauts feel dizzy for the initial day or so, before their body adjusts to liquids, if that helps you visualize it. However, on earth, I’d be inclined to say that horizontal would be better due to gravity and the direction the normal force of the fluids is pointing, but I could totally be wrong. Hope that helps.
Accelerations are sensed by your vestibular system located in your inner ear, more specifically the otoliths for linear accelerations. Your question is not very clear because you do not specify how exactly people would be moving, but let me try to answer anyway. First, in theory the otoliths detect accelerations only, so as long as you move at a constant speed in a constant direction you do not perceive your own movement (thanks, otherwise you wouldn't be able to stand being in a car, train or plane). Second, if you move in a circle horizontally it's different, and how different depends on your orientation. If you always look in the same direction, your acceleration will be a cosine function in the orientation of you head, and a sine orthogonal to your orientation (so you perceive the same as if you were on a sledge that moves back and forth and right and left, obviously as such a sledge would therefore be moving in a circle). But if you look in a direction tangent to the circle, then you are back to the case of constant acceleration and don't even perceive your own motion. Third, vertically it's even more different because of gravity. Gravity is a constant acceleration toward the earth. So you always perceive it (that's why you know the orientation of you head even with your eyes closed and even if you are not moving). So this is similar to a horizontal circle, except that it would add up to the constant pull from earth gravity. Finally in space there would be no difference between the 2 cases.
That might sound complicated, but take the example of rotations (rotational accelerations are processed by the semi-circular canal but lets neglect that). If you spin at a constant speed horizontally (alongside the vertical axis), you wouldn't be able to tell you are spinning because your acceleration would be constant. But if you spin vertically (alongside a horizontal axis), then you would always perceive you are spinning because you would always be able to perceive earth gravity (as it is an acceleration) and you would presumably get very nauseous. And again, in space there would be no difference.