Calculate Rotation Period for Amusement Park Ride

[techtrailer89]

Hi i am studying for a test and found this problem that i have no clue how to do.. I was hoping for some help with it like equation to start.
thanks

Homework Statement

In an amusement park ride called The Roundup, passengers stand inside a 14.0 m-diameter rotating ring. After the ring has acquired sufficient speed, it tilts into a vertical plane.
What is the longest rotation period of the ring such that the riders will not fall off at the top?

All i know is that the weight force much be less than normal force right? and do I use v=2*pi*r/T
I don't know where to start thanks

 

[techtrailer89]

Never mind I figured it out used V_c=(r*g)^(.5) to find v then just plug and chug

 

[Kurret]

ok great then :)