# Physics Angular Momentum Question

1. Dec 5, 2009

### gsimo1234

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!

2. Dec 5, 2009

### Cryxic

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?

3. Dec 5, 2009

### gsimo1234

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

4. Dec 5, 2009

### denverdoc

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.

5. Dec 5, 2009

### gsimo1234

that is a very very good idea..does any one else have any other tips?