Speed of Satellite at Perigee and Apogee

[bobdream]

Homework Statement

Homework Equations

g=GMm/r^2
e=c/a
g=v^2/r

The Attempt at a Solution

a) v^2/r=GM/r^2 m<<M
v^2=GM/r
v=SGRT(GM/r)

I don't think this is valid though since the orbit is not circular. I don't know how to alter the equation so it also applies to the elliptical orbit of the problem.

Thanks so much for any help.

 

[Andrew Mason]

There are two things that are conserved: angular momentum and energy. Try writing out the equation for the conservation of energy and the equation for the conservation of angular momentum and see if you can solve for the velocity at the apogee.

AM