## Essential University Physics: Volume 1 (3rd Edition)

We know the equation for the period of an orbit: $T=\sqrt{\frac{4\pi^2 r}{a}}$ We know the value of "a" is: $a = 9.81(.058)=.5684$ We use the known values, adding the radius of the earth to the altitude, to find: $T=\sqrt{\frac{4\pi^2 ((2+.6371)\times10^7m)}{.5684}}=42,773s=\fbox{11.88 hours}$