Circular motion- how slowly would you twirl the ball in vertical circle

[dani123]

Homework Statement

If you twirl a ball attached to a cord in a vertical circle, there would be a critical speed at the top for which the tension in the cord is zero. This is because the force of gravity supplies all the centripetal force necessary to complete the circle. How slowly would you twirl an 800-g ball so that it would describe a vertical circle of radius 1 m?

Homework Equations

Because we are looking for the slowest speed that the ball can have in order to complete the circle F_g=F_c
And therefore, through rearranging equations found that v=√gR

The Attempt at a Solution

So from that manipulated equation found that v=3.13m/s

If anyone could just verify my answer, that would be greatly appreciated! Thank you so much for your help and time!

 

[tms]

Looks okay to me.