Here we go:

"The magnitude F of the centripetal force is equal to the mass m of the body times its velocity squared (v2) divided by the radius r of its path: F=mv2/r."

right - and for gravity - F=ma, where 'a' as Gravity is = 9.81m/s^2....

so F=mx9.81

so combining the two equations gives: mx9.81=mv2/r...cancel m's, 9.81=v2/r...

r=2000m, so 2000x9.81=19620....so V2 = 19620, so v=140m/s...or about 500kmph...

Haven't done that for years so it may be wrong..

Dave L