Có : \(g=\dfrac{GM}{R^2}=9,8=\dfrac{GM}{6400000^2}\)
\(\Rightarrow GM=6400000^2.9,8\) .
Lại có : \(g=\dfrac{GM}{\left(R+h\right)^2}=4,5=\dfrac{6400000^2.9,8}{\left(6400000+h\right)^2}\)
\(\Rightarrow h=3044669,278\left(m\right)\approx3045\left(km\right)\)