Theoretically, could this position be maintained on a frictionless surface?

Question

click on the link for the 2 pictures....
from the pictures i have given.....

picture 1

http://i33.photobucket.com/albums/d69/EHSwrestler1/chap12_pzl_1.jpg

picture2

http://i33.photobucket.com/albums/d69/EHSwrestler1/chap12_pzl_2.jpg

Consider the following three cases?



Static case with arms not extended (first picture.)
Theoretically, could this position be maintained on a frictionless surface?

Static case with arms extended (second picture.)
Theoretically, could this position be maintained on a frictionless surface?

Transition between the static positions, Dave extends his arms and moves Demoise outward.
Theoretically, could this move be accomplished on a frictionless surface?

Answer 1

Absolutely not. To maintain any of those positions, you have to rock back a bit to compensate for the weight of the child in front of you. The weight is not perfectly centered, and therefore, the pole would slide on a frictionless surface. The child, being in front in all of the postitions you present, means that the weight is not properly centered nor distributed in any of them, and therefore none could be maintained on a frictionless surface. And the transitional scenario would cause a collapse immediately owing to the equal and opposite reaction which would result. Any movement at all would cause a collapse.

As a matter of fact, I doubt that even a perfectly centered weight could maintain this position as a practical matter. Any minute adjustment of the weight distribution, which would be necessary to maintain such a position, would cause a collapse. Therefore, the weight would have to begin perfectly centered and distributed and nothing could act on it at all without causing a collapse. If nothing else, gravity is going to act on it because the question presupposes a gravitational field.

Answer 2

Yes and no. If you started out with perfect balance and never had to make a correction and were never disturbed, both positions are stable. But any disturbance that required a correction could not be corrected. And I think the transition could be done too, if everything was perfect so that no upsetting of balance occurred during the transition. The center of gravity does not have to change during the transition, so if it were done perfectly, it would not in and of itself cause any disturbance. Of course, in reality there would be some small disturbance that would require correcting, and all would be lost after that. If the pole started tipping forward, you would have to lean back, but with no friction, the leaning back would impart an equal and opposite force on the pole making it want to slide out from under you.

Answer 3

I would have to say no to atleast the second one being that you would have to provide forward thrust causing his stilts to push apon the surface of the ground.