Angular Momentum: Physics Demonstration & Math Behind It

AI Thread Summary
The discussion centers on a physics demonstration involving a spinning wheel, or gyroscope, that maintains its orientation due to high angular momentum. Participants explore the mathematical principles behind this phenomenon, particularly the relationship between angular momentum and torque. It is noted that the torque from gravity acts in a different direction than the angular momentum, leading to precession rather than the expected downward flop. The conversation also touches on the complexity of calculating the net torque on the wheel and the changes in velocity of point masses on the gyroscope. Overall, the thread emphasizes the intriguing dynamics of angular momentum and its implications in physics.
Alkatran
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We had a demonstration in physics, which I'm sure most of you have seen, of a wheel spinning very quickly maintaing it's orientation. (There is a string hooked to one end of the axle, and you expect the wheel to 'flop' downwards)

Now, I was just wondering what the math behind this is?

The spinning wheel has a high angular momentum in direction X while there is a torque from gravity in direction Y: after that...? This is definitely similar to it being difficult to slow an airplane rather than a ball.
 
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Alkatran said:
We had a demonstration in physics, which I'm sure most of you have seen, of a wheel spinning very quickly maintaing it's orientation. (There is a string hooked to one end of the axle, and you expect the wheel to 'flop' downwards)

Now, I was just wondering what the math behind this is?

The spinning wheel has a high angular momentum in direction X while there is a torque from gravity in direction Y: after that...?

The spinning wheel is typically called a gyroscope, and the movement is referred to as precession.

I'm pretty sure that it's possible to work things out starting from linear momentum to see that there's a net torque on the wheel as a rigid object by, for example, looking at the necessary change in velocity of point masses along various places on the gyroscope to tilt the axle while the wheel remains spinning.
 
F=force
m=mass
0=theta
I want to say F=mdcos0 but I am not 100% sure, and in physics when we are not 100% sure we say were just guessing.
 
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