How is potential energy related to orbits of satellites?

AI Thread Summary
The discussion focuses on understanding the relationship between gravitational potential energy and satellite orbits, specifically for a satellite in a noncircular orbit with defined apogee and perigee distances. Participants emphasize the need to derive the general expression for gravitational potential energy using Newton's law of gravity, noting that it is influenced by the masses involved and their distance from the Earth's center. The problem requires calculating the ratio of potential energy at perigee to that at apogee. Clarification is sought on the problem's wording and concepts. Understanding these principles is essential for solving the problem effectively.
HeatherH
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Hi!

I really don't even understand what this problem is talking about! If someone could just point me in the right direction, I would appreciate it!

A satellite is placed in a noncircular orbit about the Earth. The farthest point of its orbit (apogee ) is 4 Earth radii from the center of the Earth, while its nearest point (perigee ) is 2 Earth radii from the Earth's center. If we define the gravitational potential energy U to be zero for an infinite separation of Earth and satellite, find the ratio U perigee/U apogee .

Thanks!
 
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The first sentence doesn't sound good. I mean are any words or concepts unclear in the problem's text...?

Daniel.
 
HeatherH said:
I really don't even understand what this problem is talking about!
Start by looking up (or, better yet, deriving) the general expression for gravitational potential energy, which comes from Newton's law of gravity. Hint: U depends on the masses and the distance from the center of the earth.
 

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