A satellite moves in a irregular orbit around the Earth at a
     A satellite moves in a irregular orbit around the Earth at a speed of 5.4 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 times 10^24 kg. The value of the universal gravitational constant is 6.67259 times 10^-11 N middot m^2/kg^2. Answer in units of km. 
  
  Solution
We are given...
 v = 5400 m/s
 
 The mass of Earth is...
 M = 5.98e24 kg
 
 Gravitational constant is...
 G = 6.67259e-11 Nm2/(kg2)
 
 For a circular orbit, here are two basic equations...
 v = ( G M / r )
 T = 2r / v
 where r is the orbit radius of the satellite and T is the period
 
 
 We get...
 r = G M / v² = 3.99e7 m
 
 Since Earth\'s radius is 6.37e6 m, we subtract to get...
 altitude = 3.353e7 m = 33530 km

