Physics
posted by NeedHelp! .
A rock of a mass 0.2kg is attatched to a 0.75m long string and swung in a vertical plane. What is the slowest speed that the rock can travel and still maintain a circular path.
so, i started with the following equation: Fc= mv2/r
but where do i go from there to solve for v(what can i change Fc to? )

at the top, mv^2/r=mg
or v= well you solve it. 
3 MI/HR

Oh, so the Centripetal force= mg
how though? 
Oh, 'at the top'
great, thanks for your help :) 
just to clairify,
you're suffesting that there is no tension when the rock is at the top of the swing?
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