Re: [Phys-l] velocity-dependent mass (or not)

[John Denker <jsd@av8n.com>]

On 06/30/2009 06:53 AM, WC Maddox wrote:

[scenario involving an equal-arm balance and fast-moving weights]

> .... Are both authors wrong by not bringing in 
> general relativity?

Yes.  Both wrong.

Here's another scenario that illustrates the same physics.
  http://www.av8n.com/physics/gravity-source.htm

I like this version slightly better, because the system is in a 
stationary state.  That is, all the positions and field-strengths
are the same from moment to moment.

If you analyze it using special relativity plus Newtonian gravity
(not general relativity) you get an obviously wrong answer.  If you 
bring in the usual notion of velocity-dependent mass, it just makes 
things worse.