In an old-fashioned amusement park ride called Gravitron,Starship, or Alien Abduction, passengers stand inside a 3m tall,1m diameter hollow steel cylinder with their backs against the wall. The cylinder begins to rotate about a vertical axis when a 100kg ride technician starts the ride from his booth in the center of the ride. Then the floor on which the passengers are standing suddenly drops away! If all goes well, the passengers vill "stick" to the wall and not slide. Clothing has a static coefficient of friction against steel in the range 0.14 to 0.44 and a kinetic coefficient in the range 0.00001 to 0.24. What is Che minimum rotational frequency for which the ride is safe in pm? ***Bonus*** A cylinder rolls down a ramp which is angled 30 degrees above horizontal. What is the coefficient of rolling /Friction between the cylinder and ramp which allows this cylinder to roll? Courtesy of Ashish.

Fig: 1