Calculating Rotational Speed for 2g Experience in a Rotating Machine

[jtizzleg]

Homework Statement

A NASA astronaut is placed in a rotating machine to see how well their bodies withstand G Force.
What rotational speed is needed in a device that has a 6.25 m radius to allow a 75.8 kg astronaut to experience a force that is twice his normal weight (or 2g)?

Homework Equations

Centripedal Force formula:
F = (m*v^2)/r

The Attempt at a Solution

I am wondering if that's the right equation, as it's the only equation I've found to use the radius of the machine, force, and mass given.
Just trying to confirm some things:
Do I assume the machine has no mass? No mass for the machine is given to be summed to the mass of the astronaut, so I assume that the only mass I calculate.

Do I multiply the mass by two? since I'm trying to find the speed needed for the machine to exert double his mass.

Also, is this even the right formula? Or did I get something wrong?

Edit: Scratch that second question, just figured that the Force would be the 2g, while the mass I'm assuming is his weight alone, unless I have to account for the machine's mass too.

 

[supratim1]

your formula is right. equate it with 2mg. the mass of the machine doesn't play any role.