In a "Rotor-ride" at a carnival, people are rotated in a cylindrically walled room (think of a ride like the gravitron). The room radius is 4.6m and the rotation frequency is .4 revolutions per second when the floor drops out. What is the minimum coefficient of static friction so that the people will not slip down? I understand that i need to solve for centripetal acceleration and solve for a normal force and fictional force, but I'm having trouble finding the process to get to that solution. Any help would be greatly appreciated.