What Forces Influence the Moon in the Sun's Inertial Frame of Reference?

[menager31]

What forces affect on the Moon in the Inertial frame of reference which is the Sun?
+gravity form the Sun
+gravity from the Earth
+centrifugal force from the rotationary movement of the Moon round the Earth


is this list correct?

 

[Doc Al]

+gravity form the Sun
+gravity from the Earth

Sounds good. I suspect the effect of other planets would be negligible.

+centrifugal force from the rotationary movement of the Moon round the Earth

Centrifugal force is a "fictitious" force that appears when viewing things from a non-inertial rotating frame; it's not relevant in an inertial frame.

 

[menager31]

Yes, I know that there isn't any centrifugal force in this frame from the rotating movement round the Sun, so we cannot include any fictitious forces in an inertial frame?

 

[Doc Al]

That is correct: no fictitious forces in an inertial frame.

 

[einstein_fan]

A question from Polish Physics Olympiad again...

 

[alvaros]

How do you call the force that prevents the moon falling into/to the Earth ?

 

[Doc Al]

How do you call the force that prevents the moon falling into/to the Earth ?

What prevents the moon from falling into the Earth is its speed, not a force. If you were to remove gravity, the moon would just keep going in a straight line.