How fast must the astronaut's head be moving

[dukebdx12]

Homework Statement

In this device, an arm 8.84g long rotates about one end in a horizontal plane, and the astronaut is strapped in at the other end. Suppose that he is aligned along the arm with his head at the outermost end. The maximum sustained acceleration to which humans are subjected in this machine is typically 12.5g

- How fast must the astronaut's head be moving to experience this maximum acceleration? m/s

- What is the difference between the acceleration of his head and feet if the astronaut is 2.00m tall? m/s^2

- How fast in rpm (rev/min) is the arm turning to produce the maximum sustained acceleration? 1/T= __rpm

Homework Equations

v^2/r ? something similar maybe

The Attempt at a Solution

i have probably attempted every set-up besdies the one that works. I have used the numbers in every different way to try and figure this out. I have tried 22 different ways and can not figure this out for my life

 

[TVP45]

Before setting up your calculations, think for a minute what kind of physical setup this is and what they're doing. Describe it to yourself. Draw a little sketch.