ðɪ ˈoʊnli ɹᵻkwˈaɪɚmənt ɪz ðætðə sˈɛntɹəl fˈoːɹs ɛɡzˈæktli ˈiːkwəlz ðə sˈɛntɹaɪptəl fˈoːɹs, wˌɪtʃ dɪtˈɜːmɪnz ðə ɹᵻkwˈaɪɚd ˈæŋɡjʊlɚ vəlˈɑːsᵻɾi fɚɹə ɡˈɪvən sˈɜːkjʊlɚ ɹˈeɪdɪəs.
The only requirement is that the central force exactly equals the centripetal force, which determines the required angular velocity for a given circular radius.