Uniform Circular Motion and centripetal force

AI Thread Summary
The discussion focuses on uniform circular motion (UCM) and the role of centripetal force in an experiment involving a stopper and a weight. It highlights the contradiction in maintaining a horizontal circular path, as the vertical tension required to support the stopper's mass cannot be achieved. The participants agree that a horizontal circle is not physically feasible without vertical tension. The need for experimental precision is questioned, suggesting a deeper understanding of the forces at play is necessary. Overall, the conversation emphasizes the complexities of UCM and the conditions required for stability in circular motion.
BlueEight
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Homework Statement


http://img.skitch.com/20091201-pxecs3d574itggpejybhdbp3qr.jpg

Essentially, as an experiment, our physics class whirled a stopper attached to a string that went through a tube that was finally attached to a weight on the bottom of the string.

The Attempt at a Solution


I'm not really sure, unless the centripetal force is somehow not adequate to hold the weight up, but it should be, as long as the stopper is swung around quickly enough.. This seems contradictory to everything that we've learned about UCM this semester.
 
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I think you need to show that a horizontal circle as show in the diagram is not physically possible?
 
Oh yeah! Because if it was horizontal, there would be no "vertical tension" holding up the mass of the stopper?
 
BlueEight said:
Oh yeah! Because if it was horizontal, there would be no "vertical tension" holding up the mass of the stopper?
yes

Tsinθ=mg, θ=0, the mass will not stay in a horizontal circle.
 
Ah, thanks. But why would it be "necessary for experimental precision?"
 
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