Re: [Phys-l] Relativity Question about spring

[<carmelo@pacific.net.sg>]

Hugh wrote:
> I don't think so. The issue is, what is the system. 

Have not we defined an electron or a muon as a system before? This is also known as "one-particle system". You may not have answered the question.

> But no one says that the neutron "loses such and such a 
> mass" when it becomes bound to a proton, we only talk about the 
> deuteron mass being less than the collective masses of the proton and 
> neutron as free particles.

What if some physicists and physics teachers have said something to that effect?

In fact, some astrophysicists are interested in the effective neutron mass; for those neutrons which are present in the neutron stars...

In addition, physics teachers such as Walter Scheider, the "Presidential award winning teacher", describe this in his book and website:

"Now, back to the question: what got smaller? (We don't mean smaller in size, necessarily, but in mass.) Did some of the protons get smaller? Did some of the neutrons get smaller? Did some of the electrons get smaller?

In fact, the answer to that question is "yes." But, you will respond, we've been taught that a proton has a definite mass, the mass that is listed in the tables to seven decimal places. Same for the neutron, and the electron. Surprisingly it's not quite like that......"

For more details, please refer to
http://www.cavendishscience.org/energy-flash/flash-index.htm

Alphonsus