In a "rotor-ride" at a carnival, people are rotated in a cylindrically walled "room." The room radius is 4.6 m, and the rotation frequency is .5 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 am totally confused as to how to find that with only the frequency and radius provided. I was able to find the centripetal acceleration, but I am stuck now. I don't have the mass...so what about the forces? Thank you so much for all your help.