Answer
a) $r=7.61\times10^6m$
b) $F_G=3.79\times10^4N$
c) $alt=1.22\times10^6m$
Work Step by Step
a) $r=^3\sqrt{\frac{T^2Gm}{4\pi^2}}=^3\sqrt{\frac{(6600s)^2(6.67\times10^{-11}\frac{Nm^2}{kg^2})(5.98\times10^{24}kg)}{4\pi^2}}$
$=7.61\times10^6m$
b) $F_G=G\frac{m_sm_E}{r^2}=(6.67\times10^{-11}\frac{Nm^2}{kg^2})\frac{(5500kg)(5.98\times10^{24})}{7.61\times10^6m}=3.79\times10^4N$
c) $alt=r-r_E=7.61\times10^6m-6.38\times10^6m$
$=1.22\times10^6m$