Uniform centripetal acceleration

[Panix]

Homework Statement

A small ball with a mass of 3.0kg revolves uniformly in a circle on a frictionless horizontal surface. The ball is attached to a string of 1.40m to a pin set at center of circle. The object makes 2rev/sec.

a)find the centripetal accel
b)find the tension exerted on the string

Homework Equations

ac=v^2/r
Fc= ma=m(4pi^2r/T^2)
T= .5

The Attempt at a Solution

if its uniform wouldn't the Fc=FT(force of tension)
T would =.5 because 2 rev/1 sec?
I am not sure how to find centripetal accel because i do not know how to find the velocity unless i am missing something..

 

[kuruman]

If it makes one revolution and the string is 1.40 m, how much distance does it cover?