that's not the speed of the gravity's pull, that is the acceleration due to gravity: 9.81 meters/second squared. Anyway, here is how they would do this without making us feel nausious...
Have guests on their back at first, with their heads facing inwards. Start accelerating the centrifuge, simulating the high G-Forces of lift-off.
At the right time in the video, as guests are passing out of the atmosphere, allow the centrifuge to free-spin, and at this time tilt the cabins over so that guests are now on their stomachs, head facing out. Immediately apply power to the centrifuge, and you will experience zero-gravity without any jerkiness. They would have to time this perfectly, and even so, I think this ride system will demand shoulder harnasses...perhaps there will be a way to loosen those harnasses when guests are experiencing no gravity, so they can actually feel that. If disney does this right, guests won't even feel the car as it begins to spin. All they have to do is slowly increase the car to the speed where guests experience 1 G in the sideways position, and guests won't feel as though they are falling out of their seat, nor will they notice any changes in their surrounds. Pretty kewl effect!