(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Ok so take r' to be r dot..

i have E = 1/2m (r' ^2 + h^2/r^2) - A/r = E

Energy equation for central force (inverse square)

and r = l/(1+ecostheta) where l is the latus rectum..

need to derive the expression linking E and e i.e. E= A^2/2mh^2 (e^2-1) but cant seem to get there...

any help would be great..

thanks

2. Relevant equations

3. The attempt at a solution

well for a start, when you differentiate r, the result includes a term theta dot -- where does that go?!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Orbit Parameters and Energy

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**