But the pool players won't fall over simply because you choose the ball
as your frame of reference throughout the process. You have to choose a
frame a reference which is inertial (at rest or moving with constant
velocity) throughout the entire process, i.e. before, during and after
the collision.
Anyway this is not really where I wanted to end up because I find myself
in agreement with newtonian relativity. lol
It is the ahistorical aspect of newtonian relativity which bothers me.
When I stand on shore and see a ship sail by, and I know that it was
set in motion by the wind. Also a person on the ship knows
the shore was not set in motion by the wind.
Harry
----- Original Message -----
From: leaking pen <[EMAIL PROTECTED]>
Date: Thursday, September 25, 2008 4:24 pm
Subject: Re: [Vo]:Chinese building "space drive" unit
> if you are choosing that ball as a frame of refference, then that
> would be true. The point of relativity is that there is no central
> frame of refference, just what you choose. its not conceit, its
> reality.
>
> On Thu, Sep 25, 2008 at 11:49 AM, Harry Veeder <[EMAIL PROTECTED]> wrote:
> >
> > That is true but that is not what I mean.
> >
> > Imagine you are the ball and you are resting wrt to the table and
> the> earth. A cue or another ball hits you so you move at 1 m/s wrt
> to the
> > table. Would you be so self-centred as to claim you are still
> resting,> and that the table and the earth are now moving under you
> at 1 m/s?
> >
> > If such a conceit were true the pool players standing around the
> table> would have been flung off their feet as the earth abruptly
> accelerated> under them from 0 m/s to 1 m/s.
> >
> > Harry
> >
> >
> >
> > ----- Original Message -----
> > From: leaking pen <[EMAIL PROTECTED]>
> > Date: Thursday, September 25, 2008 12:43 pm
> > Subject: Re: [Vo]:Chinese building "space drive" unit
> >
> >> Yes. It is more the opposite, but every step you take, you push
> the>> Earth, and she pushes back at you. The Earth pushes a hell of
> a lot
> >> harder, but you DO have an effect on the motion of the Earth,
> however>> infintesimal, with each step.
> >>
> >> On Thu, Sep 25, 2008 at 9:38 AM, Harry Veeder <[EMAIL PROTECTED]>
> wrote:>> >
> >> >
> >> > ----- Original Message -----
> >> > From: "Stephen A. Lawrence" <[EMAIL PROTECTED]>
> >> > Date: Thursday, September 25, 2008 11:18 am
> >> > Subject: Re: [Vo]:Chinese building "space drive" unit
> >> >
> >> >>
> >> >>
> >> >> OrionWorks wrote:
> >> >> > I bet this device look familiar to a few vorts!
> >> >> >
> >> >> > See:
> >> >> >
> >> >> > http://blog.wired.com/defense/2008/09/chinese-buildin.html
> >> >> >
> >> >> >
> >> >>
> >> >> Uh -- not me; looks sort of like an antique picture tube, maybe,
> >> >> but I
> >> >> don't recognize it.
> >> >>
> >> >> I notice Emdrive hasn't gotten as far as running a spell checker
> >> over>> their front page, which doesn't automatically fill one with
> >> >> confidence.
> >> >> From the description, it appears to be a microwave oven.
> >> Surprising>> that they claim it will fly.
> >> >>
> >> >> I had one other comment on the website. On the theory page,
> >> they say:
> >> >>
> >> >> > ... Einstein's Special Law of Relativity in which separate
> >> frames of
> >> >> > reference have to be applied at velocities approaching the
> speed>> >> of light.
> >> >>
> >> >> This is absolutely false. SR does *not* require that you must
> >> apply>> "separate frames of reference" when approaching the speed
> >> of light.
> >> >> In
> >> >> fact any analysis which relies on total momentum or energy
> >> *must* be
> >> >> carried out entirely within a *single* reference frame or else
> >> you'll>> end up with nonsensical results (just as they have
> >> apparently done
> >> >> here).
> >> >> In the FAQs they say:
> >> >> > Thus the system of EM wave and waveguide can be regarded as an
> >> open>> > system, with the EM wave and the waveguide having separate
> >> frames of
> >> >> > reference.
> >> >>
> >> >> This is complete nonsense. The "reference frame" chosen is
> >> based on
> >> >> what makes it easiest to solve a particular problem. There's
> >> nothing>> magical about relativity theory here, nor is there any
> >> mystical>> significance to the term "reference frame"; *exactly*
> >> the same concept
> >> >> exists in ordinary Newtonian mechanics.
> >> >>
> >> >> When a pool player strikes a ball, in the frame of the table,
> >> the cue
> >> >> and the player's arm have significant momentum just before the
> >> ball is
> >> >> hit. Afterwards, the table, player, and cue have zero momentum
> >> in the
> >> >> *table's* reference frame. And yet, the ball has zero momentum
> >> in the
> >> >> *ball's* reference frame, too! So, where did the momentum go?
> >> >> Answer:
> >> >> you need to do the momentum budget using a *single* frame,
> not a
> >> >> different frame for each physical object! (But you get to pick
> >> which>> frame to use.)
> >> >>
> >> >
> >> > I have difficulty even accepting newtonian relativity.
> >> > Do you think by a flick of the wrist the mass of the table
> (and the
> >> > earth!) have gone from being at rest wrt to the cue ball, to
> >> being in
> >> > motion wrt to the cue ball?
> >> >
> >> > Harry
> >> >
> >> >
> >>
> >>
> >
> >
>
>
