Uniform circular motion - stone in pail

1. The problem statement, all variables and given/known data
A stone rests in a pail that is moved in a vertical circle of radius 60 cm. What is the least speed the stone must have as it rounds the top of the circle if it is to remain in contact with the pail?
Answer: 2.4 m/s

2. Relevant equations

v= 2 pi r / t

3. The attempt at a solution

v = 2 pi .6 / t

v= 3.77 / t

How do I figure out what T is? Am I using the right formula? Please answer, thanks.
Anyone? I just need help on getting the problem started :/

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