A gravitron is moving at great speed. When the FLOOR drops away (greased to make friction negligible), does the person stay pinned to the wall or does the person slide to the bottom? If the walls were not greased, we know that centrifugal force pushes an individual against the wall, and the reaction force of the wall balances this force so he is at rest with respect to the rotating frame, so that he stays pinned to the wall. The only force to balance the downward gravitional weight force is the upward frictional force between a rider and the wall. So, if the walls were greased--thereby taking away frictional force-- is there any other force/variable that keeps the rider pinned to the wall instead of sliding down? I was thinking that when a gravitron accelerates to a high enough velocity, it can escape gravity. At the gravitron speed, the riders are experiencing centripetal force equivalent to four times the force of gravity. I am wondering why this is (does the acceleration affect the weight/mass and if so, how?) and if, without the frictional force, this speed would still cause the rider to overcome gravity and stay pinned?