If the coefficient of friction is 0.41 and the cylinder has a radius of 2.5 m, what is the minimum angular speed of the cylinder so that the people don't fall out? (Normally the operator runs it considerably faster as a safety measure.)

I am not seeing the physical setup here.

its like the amusement park ride where people stand against a wall and the floor drops out..

OK, the force of friction is mu*normal component.
The normal component is mass*w*radius where w is in radians/sec. The force of friction needs to be greater than mg, so

mu*mass*w radius > mg

solve for w.