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Explaining gyroscopic precession with linear vectors?

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Jd0g33
#1
Aug25-13, 09:26 PM
P: 293
For example, an explanation as to why a gyroscope resists movement is because every point on the wheel has a linear velocity of a certain speed and it would take a sufficient amount of force to change its direction.

So could you also explain gyroscopic PRECESSION using only the linear quantities? (Instead of angular quantities, like torque and angular momentum, like its usually explained).
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eigenperson
#2
Aug25-13, 09:56 PM
P: 160
Larry Gonick has an explanation in the Cartoon Guide to Physics. You can see it on Google Books (or at least I can):

The Cartoon Guide to Physics - Larry Gonick - Google Books

Whether you buy this explanation is another question, of course. I believe the general idea behind the explanation is correct, even though there are some things in the diagrams that aren't.
Jd0g33
#3
Aug25-13, 10:54 PM
P: 293
Wow, eigenperson, that is exactly what I was looking for. Thanks for all your help tonight!

What is it about the diagram that you feel is incorrect? Seems legitimate to me (but what do I know)

eigenperson
#4
Aug25-13, 11:14 PM
P: 160
Explaining gyroscopic precession with linear vectors?

Well, I'm not absolutely convinced those vectors are accurate depictions of the "flopping" forces. And there is a similar problem with the diagram that shows the resulting velocities (actually, that one I know is wrong, because if the sides of the wheel were moving with those velocities, it would rotate about a vertical axis passing through its own hub instead of an axis passing through the point of suspension).

Even if I'm right about these inaccuracies, I think the logic overall is correct. There's just a lot more detail than he shows.
kg4pae
#5
Aug25-13, 11:29 PM
P: 27
Quote Quote by Jd0g33 View Post
For example, an explanation as to why a gyroscope resists movement is because every point on the wheel has a linear velocity of a certain speed and it would take a sufficient amount of force to change its direction.

So could you also explain gyroscopic PRECESSION using only the linear quantities? (Instead of angular quantities, like torque and angular momentum, like its usually explained).
Aside from the fact that this question appears to have some built-in wrong assumptions, it is a bit like asking if it is possible to explain a circle with only lines. The answer to both is "not very well".

At any rate, there is a good explaination of gyroscopes and precession at
The Annenberg Project / The Mechanical Universe Episode 20
Just make sure you enable pop-ups, otherwise you will not be able to see it.


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