Finding Velocity?

Question

You swing a 2.60kg stone in a circle, using the full length of a thin 80.0cm rope.
At what speed should you swing it so its acceleration will be 9.8 m/s^2 ?

Answer 1

centripetal accel a = v^2/r = 9.8 m/s^2
r = 0.8 m
v (in m/s) = sqrt(0.8*9.8)
Note: mass is irrelevant.