Re: "Dissipation" (was Re: momentum conservation(2))

[Tim Burgess <tburgess@JAGUAR1.USOUTHAL.EDU>]

On Wed, 15 Mar 2000, John Mallinckrodt wrote:
> On Wed, 15 Mar 2000, Tim Burgess wrote:
> > To test my idea you could take the locked carts and carefully (with
> > one stationary) pull one away from the other with a thread.  You will
> > find that once the cart "tears free" it is launched with a small
> > velocity.  Measuring the velocity of this "launched cart" may reveal
> > a major portion of your energy labeled as "dissipated".  Just an idea.
>
> Velcro in its intended use does not store any significant amount of
> potential energy.  When two carts equipped with velcro collide, the "lost"
> kinetic energy is indeed *dissipated*, not transformed into potential
> energy of bent velcro barbs.  If you find that the cart is launched with a
> small velocity after being torn free, it is simply because you were
> exerting a force on it in order to tear it free and *kept* exerting that
> force for a short time *after* it broke free.

Possibly a force probe at the edge of detection could help? I picture
the barbs as once "unhooked" as "pushing" on the cart.  You may have
caught me with a "wrong" picture!

I do very much appreciate your insight and pointed correction. If I
were to remove the velcro I do not think it is at possible that there
would be as much KE energy loss as there is WITH the velcro (they do
"bounce" without velcro) . If you do think this is "dissipation" then you
hold that there is a greater rise in thermal with the velcro?
(My estimates places the rise as so small that it is undetectable)

Is there some way to test our differences? I would be willing to try
(or supervise a try) some empirical test...if at all possible.

Oh well.....so much for science as an empirical creation of knowledge!
Thanks!

Tim Burgess
UMS-Wright Prep
Mobile, AL 36606

> John Mallinckrodt      mailto:ajm@csupomona.edu
> Cal Poly Pomona          http://www.csupomona.edu/~ajm