Uniform circular motion

[Jt00]

A ball attached to a string is being swung in a circle. How long does it take the ball to complete one revolution if its mass is 3.4 kg, the string is 1.2 m long, and the tension on the string is 269 N?

I'm confused on the equations. \(\displaystyle T=\frac{2\pi{r}}{v}\) and \(\displaystyle v=\frac{2\pi{r}}{T}\)

T=period (time it takes for the object being swung to complete one revolution)
r=radius
v=velocity

Velocity is not given. To find velocity, I have to find the period, which is what I'm trying to solve for.

 

[wjm11]

A ball attached to a string is being swung in a circle. How long does it take the ball to complete one revolution if its mass is 3.4 kg, the string is 1.2 m long, and the tension on the string is 269 N?

I'm confused on the equations.

and

T=period (time it takes for the object being swung to complete one revolution)
r=radius
v=velocity

For circular motion, a = v^2/r ; F = ma = m(v^2/r); Therefore, v = (Fr/m)^.5

You know m, r, and F. Solve for v, then plug that into your T eqn.