Circular Motion --> amusement park ride 1. The problem statement, all variables and given/known data A gravitron ride at a fair consists of a large 15m cylinder, which rotates about a vertically oriented axis of symmetry. The rider is held to the inner cylinder wall by static friction as the bottom of the cylinder is lowered. If the coefficient of static friction between the rider and the wall is 0.8, then how many revolutions per minute must the cylinder execute? 2. Relevant equations Fc= m vsquared/r Fg= mg 3. The attempt at a solution I don't really know where to start on this one. all i know is that i have to set up an equivalency, and that mass will somehow end up canceling out. Please help me out here, it would be greatly appreciated! Thanks in advance!!!