## Physics: Principles with Applications (7th Edition)

$1.2 \times 10^{-10}m$.
Treat the 2 oxygen molecules like point masses of mass M/2, each a distance D/2 from the axis of rotation. $$I=(M/2)(D/2)^2+(M/2)(D/2)^2=\frac{1}{4}MD^2=1.9 \times 10^{-46} kg \cdot m^2$$ Use the given M and solve for $D=1.2 \times 10^{-10}m$.