A satellite of mass 
kg is in an elliptical orbit
around the Earth. At perigee it has an altitude of 1,100 km and at apogee its
altitude is 4,100 km.
(a)What was the minimum energy needed to place this satellite in orbit?
(b) How fast is it travelling at perigee and apogee?
(c) What is its angular momentum about the centre of the Earth?
[Hints can be found here, but do not follow this link until you have attempted the question on your own.]