My dynamics lecture notes repeat the Earth's equatorial bulge can be approximated as: $$ \approx \frac{\Omega^2R}{g} \approx \frac{1}{300} $$ (Do they mean R/300?)
They also include statements like:
"The Earth's oblateness $ \frac{I_3-I_1}{I_1}\approx \frac{\Omega^2R}{g} \approx \frac{1}{300} $"
Could anybody explain where this comes from? I have tried several ways to balance the gravitational and centripetal forces but I never seem to arrive at the correct result and cannot get my head around this concept.
