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I need to prove something explictly, problem is, i dont know where to start.

In orbits, we can show that the motion of 2 bodies interacting with each other only by central forces can be reduced to a an equivalent one-body problem. This is by using a Lagrangian, and by introducing an 'equivalent' mass.

The question is to show that this is possible even if these bodies are in an external uniform gravitational field.

I dont know where to start. I cant see how a gravitational field will affect the Lagrangian, because a graviatational field will just affect the potential energy term. This isnt really solving it explicity though...

any ideas where to start?

Cheers

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# Homework Help: Orbit derivation

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