Re: Special Relativity ?

[Bob Sciamanda <trebor@VELOCITY.NET>]

Hi Ken,
In your inelastic collision, the final (rest) mass of the combination is
larger than the sum of the masses of the colliding particles.  In
relativistic collisions, the momentum - energy four vector must be
conserved.  This requires that the mass change in inelastic collisions,
to keep the total energy constant.  I think Feynmans' lecture text gives
a good treatment of this.

-Bob

Bob Sciamanda
Physics, Edinboro Univ of PA (ret)
trebor@velocity.net
http://www.velocity.net/~trebor
-----Original Message-----
From: Ken Fox <kfox@STEGA.SMOKY.ORG>
To: PHYS-L@LISTS.NAU.EDU <PHYS-L@LISTS.NAU.EDU>
Date: Tuesday, November 24, 1998 5:32 PM
Subject: Special Relativity ?


> This is a question of momentum as seen from two reference frames S and
S'.
> S' is moving at 0.5c rel to S. S observes two bodies approaching each
> other so that he measures the speed of each to be 0.5c one parallel to
> the motion of S', the other directly opposed. One rest mass is twice the
> other. The two hit
> and somehow stick together. ( Is that conceivable in this thought
> experiment?)
>
> Using expressions for relativistic momentum p = gamma m v we came up
with
> a reasonable answer for the velocity of the combined mass. Of course S'
is
> supposed to agree that momentum is conserved. New values but
conservation
> none the less. Using the velocity transformantion equations and momentum
> equations, I am unable to show that as a fact.
>
> As you can tell I am a novice but a fascinated one and one who believes
he
> is making progress in understanding. But I am baffled. Any guidance
would
> be wonderful.
>
> Thanks!
>
> Ken Fox
> Smoky Hill High School
> 16100 Smoky Hill Rd
> Aurora,CO 80015
> 303-693-1700(w)
> 303-850-7537(H)
> kfox@stega.smoky.org