for circular motion we know that
F=ma=v^2/r
Therefore:
v = sqrt (rma)
Also, for cicular motion:
rev/min. = 60v/(2r*pi)
So your equation is:
rev./min = 60sqrt(rma)/(2pi*r)
For the mass (m) we can just use 1 kg.
rev./min = 60sqrt(730*1*9.8)/(2pi*730) =60sqrt(7154)/(4584.4)
rev./min = 60sqrt(7154)/(4584.4) =1.11 rev/min
the answer is 1.11 rev/min