Rotation of cylindrical habitat in space

[tubworld]

I have this question on this article by G.K. O'Neill,1974. who proposed having a cylindrical habitat in space. Then the article posed a question asking me to ponder on the speed of the rotation of the cylinder such that it wld imitate Earth's gravitational field at the walls of the cylinder given that it is 6.07 km in diameter and 30km long. It rotates abt its long axis. My working is as follows but am unsure if I am right cos I don't seem to use the information on the length of the cylinder.

radius = 6.07/2km
Since rw^2 = 9.8, and w = 2PI * f, where w=angular velocity and f=frequency,

we solve for f to get the ans.

From what I have the ans for f is 0.009043859 rev/s . am i right? If not any hints? Cos i don't seem to get the ans.

 

[FredGarvin]

You seem to be OK. The centripital acceleration does not get influenced by the length of the cylinder. It is only a function of the radius and the angular velocity.