Physics Angular Momentum Question

AI Thread Summary
The discussion revolves around the impossibility of the Earth spinning fast enough to match its orbital angular momentum due to gravitational forces. Participants calculated the Earth's spin angular momentum (Lspin) and orbital angular momentum (Lorbit), finding that Lorbit is greater than Lspin. The key point is that if the spin angular momentum were to equal the orbital angular momentum, the resulting spin velocity would likely exceed escape velocity, which is not feasible. Suggestions for tackling the problem include examining the relationship between spin and orbital dynamics under gravitational constraints. Understanding these principles is crucial for solving the posed physics problem effectively.
gsimo1234
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Why is it, in terms of gravitational forces (not relativistic terms), impossible that the Earth spin so fast that it have as much angular momentum in its spin as in its orbit?

I'm stuck on this practice problem; I'm not even sure where to start. Any clues and important tips would really help. Thanks for the help!
 
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gsimo1234 said:
Why is it, in terms of gravitational forces (not relativistic terms), impossible that the Earth spin so fast that it have as much angular momentum in its spin as in its orbit?

I'm stuck on this practice problem; I'm not even sure where to start. Any clues and important tips would really help. Thanks for the help!

This question seems confusing. Are you saying something to the effect of...the Earth can't spin too fast because its intrinsic angular momentum would have to equal its orbital angular momentum?
 
Well, as practice, i calculated the Lspin of the Earth (Iw) and Lorbit of the Earth (r x p)..Now, the Lorbit>Lspin. So the question is, why can't the spin angular momentum be equivalent to the orbit angular momentum. The answer has something to do with gravitational forces or something
 
gsimo1234 said:
Well, as practice, i calculated the Lspin of the Earth (Iw) and Lorbit of the Earth (r x p)..Now, the Lorbit>Lspin. So the question is, why can't the spin angular momentum be equivalent to the orbit angular momentum. The answer has something to do with gravitational forces or something

One idea is this: assume the condition is true--that the spin angular momentum is equal to the orbital. Then calculate whether the spin velocity is so great that the Earth's surface velocity doesn't exceed the escape velocity or something crazy. Just a notion.
 
that is a very very good idea..does anyone else have any other tips?
 

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