Re: [Phys-l] Relativity Question

[Ludwik Kowalski <kowalskil@mail.montclair.edu>]

OOPS, dm=10^-16 kg; sorry for the mistake. You can add by saying "no 
wander special relativity was not discovered by Newton."


On May 6, 2007, at 4:02 PM, Ludwik Kowalski wrote:

> On May 6, 2007, at 3:28 PM, David Abineri wrote:
>
> > I am looking for a high school level explanation for the following
> > question.
> >
> > Does a compressed spring have more mass than a relaxed spring (at its
> > natural length) by virtue of it's having more energy while compressed?
> >
> > Or, perhaps more generally, how does potential energy figure in to a
> > relativistic point of view.
> >
> > I know this is a little vague but perhaps someone who understands my
> > question might attempt a response appropriate to a high school level
> > class.
>
> 1) Yes, but this is not measurable. For example, suppose a force F=100
> N is used to compress the spring by d=0.1 m. The work done on the
> spring is 10 J. That is by how much its potential energy is increased.
> Divide this by c^2 to see that the mass increases by about 10^-19 kg.
>
> 2) Why do you have to explain this? Probably because you are probably
> dealing with relativity. In that case you already introduced the
> E=m*c^2 formula, probably giving some experimental evidence of its
> validity. That is probably enough for high school.
> _______________________________________________________
> Ludwik Kowalski, a retired physicist
> 5 Horizon Road, apt. 2702, Fort Lee, NJ, 07024, USA
> Also an amateur journalist at http://csam.montclair.edu/~kowalski/cf/
>
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_______________________________________________________
Ludwik Kowalski, a retired physicist
5 Horizon Road, apt. 2702, Fort Lee, NJ, 07024, USA
Also an amateur journalist at http://csam.montclair.edu/~kowalski/cf/