Find the speed necessary for the given circular orbit around Earth. Let GM = 9.56×10^4 cubic miles per second
per second, and assume the radius of Earth is 4000 miles.
The orbit of a communications satellite r miles above the
surface of Earth that is in geosynchronous orbit. [The satellite
completes one orbit per sidereal day (approximately 23 hours,
56 minutes), and therefore appears to remain stationary above
a point on Earth.]