a satellite moves in a circular orbit around the earth at a speed of 6 km/s. determine the satellite's altitude above the surface of the earth. assume the earth is a homogeneous sphere of radius 6370 km and mass 5.98 x 10^24 kg. the value of the universal gravitational constant is 6.67259 x10^-11 N*m^2/hg^2. Answer in units of km.