In a classic carnival ride, patrons stand against the wall in a cylindrically shaped room. Once the room gets spinning fast enough, the floor drops from the bottom of the room! Friction between the walls of the room and the people on the ride make them the "stick" to the wall so they do not slide down. In one ride, the radius of the cylindrical room is R = 7.1 m and the room spins with a frequency of 19.4 revolutions per minute.
What is the minimum coefficient of friction needed between the wall and the person?