1. The problem statement, all variables and given/known data Riders in a carnival ride stand with their backs against the wall of a circular room of diameter 8m. The room is spinning horizontally about an axis through its center at a rate of 45 rev/ min when the floor drops so that it no longer provides any support for the riders. What is the minimum coefficient of static friction between the wall and the rider required so that the rider does not slide down the wall? 2. Relevant equations mv^2 / r mg 3. The attempt at a solution I tried to convert 45 rev / min into 3/4 rev / sec. From there, I found that it covered 6 pi m / s using the fact that circumference is 2pi r. Then I drew a free body diagram with centripetal force, weight, and normal. From there I got lost regarding the relationship between normal and centripetal force.