Physics Angular Momentum Question

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Homework Help Overview

The discussion revolves around a physics problem related to angular momentum, specifically comparing the angular momentum of the Earth's spin to its orbital angular momentum. Participants are exploring the implications of gravitational forces in this context.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants are attempting to calculate the spin angular momentum (Lspin) and orbital angular momentum (Lorbit) of the Earth, noting that Lorbit is greater than Lspin. Questions arise about why these two forms of angular momentum cannot be equivalent.

Discussion Status

Some participants are offering ideas and calculations, while others are seeking additional tips and clarification on the underlying principles. There is an ongoing exploration of the relationship between spin and orbital angular momentum, particularly in relation to gravitational forces.

Contextual Notes

Participants are working under the assumption that the problem must be approached without relativistic considerations, focusing solely on gravitational forces. There is also a mention of escape velocity in relation to the Earth's surface velocity.

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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