Re: [Phys-l] force +- momentum flow

[JMGreen <jmgreen@sisna.com>]

> The "Newton's Cradle" toy is valuable for teaching about

   the work/energy theorem.

Do work on ball #1 ie

> Pull back ball #1 while leaving the others dangling at rest.
> Release ball #1.

Ball #1 strikes ball #2 and does work on it -- Ball #2 also does 
~equal work on ball #1 and stops it

Ball #2 strikes ball #3 and does work on it -- etc etc etc

Ball #6 ends up with the same level of energy that ball #1 had at the start.

Nothing flows.  Work is done.  Energy levels change, but nothing flows.

The fact that energy is conserved has nothing to do with the flow of anything.

Saying so is equivalent to saying momentum is spelled with an "m" 
therefore it flows.

Jim