Let's say you have two rings. Both rings have the same radius and are aligned so that the holes are perfectly parallel to each other and a straight line can be drawn through them without interference. Both rings spin along the same axis with the same speed, but in opposite directions. If you put a person on ring A and a person on ring B, they both experience the centripetal force of acceleration that pushes them towards the outside of the ring. Here is what I cannot understand. From the perspective of person A, he is not spinning. Both ring A and himself are stationary with some force that is pushing himself away from the center of his ring. But in reality, ring A is spinning at a speed of V, and to person A, person B should be spinning with a speed of 2V as he is spinning in the opposite direction. If person A knows of the centripetal acceleration formula, they would calculate person B's acceleration as (2V)^2/R. Person B's actual acceleration is only V^2/R, just like person A's, but person A would see the other's acceleration as (2V)^2/R, which is 4 times what it actually is. Is there an error to my thought process, and if so what am I missing? In this universe there are no stars, no planets, just the two rings and the two people.