Re: [Phys-l] [ap-physics] The Swinging Bucket Problem

[Bernard Cleyet <bernardcleyet@redshift.com>]

"The string is not touching the water.  Hence the string is exerting no
force on the water."
__

This is meant as a joke?

bc

Jeffrey Schnick wrote:

> > > "how fast do I have to spin a bucket in a vertical circle to avoid 
> > > water spilling out?" problem.  It's got plenty of 
> > >      
> > subtleties to help 
> >    
> >
> > > divide those who really understand the situation from the plug and 
> > > chuggers (for instance, anyone who draws tension in as a 
> > >      
> > force on the 
> >    
> >
> > > water is probably not thinking too carefully about the situation).
> > > . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
> > >      
> > I am puzzled by the obvious derision being heaped upon 
> > someone who would include the tension in the string in his 
> > analysis. The AHA! moment here is when one realizes that as 
> > the speed is lowered the acceleration at the top is provided 
> > less and less by the tension while the gravitational force 
> > (weight) remains the same - eventually becoming the only 
> > force needed to ensure the circular motion. I would suspect 
> > that any approach which uses a free body diagram that does 
> > not include tension is simply guess work on the student's part.
> >
> > Bob at PC
> >
> >    
> The string is not touching the water.  Hence the string is exerting no
> force on the water.
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