In a Carnival Ride,passengers Stand with Their Backs Against the Wall

Multiple Choice

In a carnival ride,passengers stand with their backs against the wall of a cylinder.The cylinder is set into rotation and the floor is lowered away from the passengers,but they remain stuck against the wall of the cylinder.For a cylinder with a 2.0-m radius,what is the minimum speed that the passengers can have so they do not fall if the coefficient of static friction between the passengers and the wall is 0.25?

A) 8.9 m/s
B) 2.3 m/s
C) 3.0 m/s
D) 4.9 m/s
E) It depends on the mass of the passengers.