Changing axis of a rotating wheel

AI Thread Summary
The discussion focuses on the dynamics of a woman standing on a rotating disc while holding a rotating wheel. When she changes the wheel's axis from vertical to horizontal, it creates a complex motion where a point on the wheel's rim traces a helix shape. The challenge lies in the need for the woman to apply a force to generate sufficient torque to change the wheel's orientation, particularly when the wheel is rotating quickly. This involves understanding the relationship between torque, angular momentum, and moment of inertia in rotational dynamics. The equations of motion indicate that altering the wheel's orientation requires significant adjustments in torque and angular momentum.
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Homework Statement


Imagine a woman standing on a rotating disc (D) with a rotating wheel in her stretched arms (se picture here: http://image.vandrermodlyset.net/rotation.jpg ). The wheel is oriented in a horizontal plane, with the rotating axis (W) of the wheel parallel to that of the rotating woman (O) – that is vertical. This situation is rather stable as long as the woman doesn’t get nausea or tired arms. In situation A: W = O = D.
Lets say that she would suddenly change the axis of the rotating wheel (W) so that it became horizontal (situation B), and the wheel would now be oriented in the vertical plane intersecting the axis of the woman (O and D). A point on the outer rim of the wheel would form a helix-shape as the woman rotates on the disk.
I know that this task (going from situation A to B) will be difficult, even more when the wheel rotates fast, but how can I prove this using equations from rotational dynamics.

Homework Equations


T (torque) = r X F
L (angular momentum) = r x p

The Attempt at a Solution


The torque of the rotating woman rotates vetor L of the wheel until it becomes parallel to W=O=D
 
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. When the woman then changes the orientation of the wheel, the torque will have to change as well, since there is a moment of inertia connected to it. This means that in order for the woman to change the orientation of the wheel, she has to apply a force F at the point r of the wheel and generate a larger torque T. The angular momentum of the wheel will also have to be changed since it depends on the force applied.
 
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