I Changing the RPM of a frictionless spinning wheel in a box

[SpaceThoughts]

Imagine a spinning wheel built into a hand size vacuum box. There is no friction between the axe bearings of the wheel and the box. Let's say that the wheel rotates with 60 RPM. Am I right if I assume:

1. The wheel continues to rotate, approximately as if in space.
2. It is not possible to change the 60 RPM in any way, as long as the box and the content is not broken. No matter how we twist and turn the box from the outside.

 

[berkeman]

How is the wheel axle attached to the interior of the box? How does gravity play in all of this?

Also, you can certainly design things to be able to add rotational energy to the spinning wheel, such as using a rotor from an electric motor as your spinning wheel...

 

[SpaceThoughts]

Let me ask the same question in a less confusing way:

I lift the front wheel of my bike off the ground and make it spin. I turn the handlebars right-left-right-left.
I feel the resistance of moving the handlebar back and forth. The faster the wheel spins the more resistance.

Will turning the handlebar back and forth change the RPM of the bike wheel, or would the wheel continue to rotate with the same RPM if there were no friction?
From my experience I think the RPM would not change, but I have not found a clear answer to this question.

 

[Filip Larsen]

Will turning the handlebar back and forth change the RPM of the bike wheel, or would the wheel continue to rotate with the same RPM if there were no friction?

For the ideal case with no axial friction and, say, a perfectly rigid wheel your experience is correct. To see this you could perhaps ask yourself what mechanical quantity usually is conserved in cases of no friction and see if this helps you conclude something. This will also explain why the wheel, in addition to the axis bearings, has to be idealized (i.e. have no internal friction).

 

[jbriggs444]

One needs the assumption that the wheel is balanced.