Physics (10th Edition)

The radius of the chamber is $1.52m$.
We know that the speed of the outer wall $v=3.2m/s$, mass of the person $m=83kg$ and the force $F_c=560N$ To find $r$, we rely on the formula $$F_c=\frac{mv^2}{r}$$ $$r=\frac{mv^2}{F_c}=1.52m$$