Let’s say you’re riding one of those gravitron rides that are common at carnivals but this one is different. It’s a gravitron inside a gravitron and you’re in the inner gravitron. The outer gravitron spins clockwise and the inner gravitron along with it fast enough so that you feel 3 G’s of force. While the outer gravitron is spinning clockwise the inner gravitron begins to spin counter clockwise fast enough to simulate 3 G’s of force. Since the inner gravitron is spinning the opposite direction as the outer gravitron would you feel O G’s of force or 6 G’s of force?
Follow up question if the force is doubled. You have the outer platform spinning one direction and the inner platform spinning the opposite direction at the same speed. Relative to the earth it would look like the person riding the inner platform is standing still. Could anti gravity be simulated by tilting the ride 90° so that the rider is constantly facing the ground while feeling 6 G’s of force pushing him upward?
In: Physics
The key thing you are missing here is this: Acceleration is not relative. It’s absolute.
If you are inside a closed box, you can determine that you are accelerating, but you cannot determine your speed. The obvious example of this is shutting the window blinds while sitting in a passenger jet, or trying to sleep while someone else is driving; your inner ear can easily tell that you are accelerating even though you have no external references.
So the force that you end up feeling would depend entirely on whether you are accelerating or not. That’s not particularly clear from how you’ve phrased the question, but if you’re saying that “Relative to the earth it would look like the person riding the inner platform is standing still” then that suggests that the person on the inner platform is going to feel the same acceleration they would if they were stationary on the earth, i.e. 9.8 mps towards the earth’s core.
First question it doesn’t really work that way. The force that you feel is a result of you going in a circle. The graviton is what spins you around yes, but the actual force you feel depends on how fast you are going, not the machine.
Like if you were to just run in a circle in the opposite direction inside a graviton (or more realisticly drive a motorcycle inside) you could cancel out the rotation and it would basically be just like running on a treadmill.
Same principle with he second 90degree setup. You aren’t moving relative to earth so you feel gravity as normal.
What matters is how fast your body is moving. So if you put one gravitron inside another one and both are spinning at the same speed, you’re stationary and it would feel exactly the same as if both gravitrons were not spinning.
Yes, but not for long.
Centrifugal force is caused by your trajectory being redirected out of the normal straight line trajectory.
So when you turn in circle you constantly get redirected to the same side, and that’s why you feel an acceleration in the opposite direction. If you manage to be in a spot where the two spinning things cancel out and you go in a straight line, it don’t move, then you will feel no acceleration.
Unfortunately, in the design you described you will eventually reach the end of the outer gravitron, and that’s where the two nested gravitron will work together to accelerate you towards the center, and you will suffer lots of G.
(Just gonna address the first part of your question where the two centrifuges spin in the same plane.)
For a brief moment, yeah, you could feel 0 G’s of force in a device like this. But only for a particular moment in the spin of the inner gravitron, when the directions of these two accelerations are opposite. Remember that to produce this centripetal force, you need to be spinning in a circle, and if you want to produce a specific *amount* of force, you’re constrained in choosing either the radius of the circle or the rate of spin. If they’re different radii, then, you can’t ‘sync up’ so that they’ll always be in opposite directions.
For part of the spin, the two nested centrifuges could produce force in opposite directions, and could cancel each other out, and for some part of it, they’ll produce force in the same direction, and you’ll have to add them rather than subtract them. And this is the case whether the two centrifuges spin in the same direction or opposite direction.
So, with appropriate choices for the radius and speed of the two spinning parts, you could make a gravitron-within-a-gravitron which violently jerks you back and forth between experiencing O G’s and 6 G’s. That’s about the best we can do.
If you watched someone in a nested centrifuge from above, the path they would follow belongs to one of two classes of curves called [epitrochoids](https://en.wikipedia.org/wiki/Epitrochoid) and [hypotrochoids](https://en.wikipedia.org/wiki/Hypotrochoid), which happen to be exactly the kinds of curves you can draw on your Spirograph.
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