What is the Required Centripetal Acceleration for a Stone to Reach 25 Meters?

[gonzalo12345]

Homework Statement

You plan to throw stones by using a sling of length 1.3 m which you whirl over your head. Suppose you wish to throw a stone a distance of 25 m. What must be the centripetal acceleration of the stone just before its release if it is to reach this distance? Assume that the release height is 2.7 m.

Homework Equations

ac = v^2/r = (w^2)r = (4((pi)^2)r)/(T^2)

The Attempt at a Solution

I really don't know how to start this problem

 

[Doc Al]

First figure out how fast you have to throw the stone to reach that distance. Hint: Assuming the stone is released horizontally, how long is it in the air?