That is not correct Robin.  Kinetic energy is calculated directly by the 
magnitude of relative velocity of the ship to the observer and therefore the 
second guy sees essentially no net change in kinetic energy once the drive 
cycle is completed.  Also notice that the energy is nonlinear with velocity.  
The fact that it is proportional to the second power of the velocity allows the 
direction to become unimportant.

I am beginning to suspect that you are playing games at this point.  All you 
need to do is to look up the definition of kinetic energy to see that what I am 
stating is correct.  I have no idea why you think kinetic energy has anything 
to do with the change in velocity instead of the net relative velocity.  
Perhaps you can quote a source. ;)

Dave

 

 

 

-----Original Message-----
From: mixent <[email protected]>
To: vortex-l <[email protected]>
Sent: Fri, Nov 28, 2014 4:02 pm
Subject: Re: [Vo]:They call me a moron. A reply.


In reply to  David Roberson's message of Thu, 27 Nov 2014 23:47:17 -0500:
Hi Dave,
[snip]

The "v" in the formula Ek = 1/2 mv^2 actually applies to the change in velocity,
not velocity in any absolute sense. For the sake of convenience, we normally
choose a frame of reference in which the initial velocity is zero which makes
the calculation simpler.

For observer 1, the change is 1/2 * m * (2-0)^2 = 1/2 * m * (2)^2.
For observer 2, the change is 1/2 * m * (1 - -1)^2 = 1/2 * m * (2)^2. 

I.e. they both see the same change in kinetic energy. 

Note 1: I have not included the dimensions here to keep the formula as simple as
possible in ASCII text.
Note 2: Depending on the initial direction of motion, you may choose to write
the equation for observer 2 as 1/2 * m * (-1 - 1)^2 = 1/2 * m * (-2)^2, however
this still gives the same result for the kinetic energy change.

>
> Robin, I just came up with a thought experiment that lends support to the 
> idea 
that a reactionless drive is not likely to exist.  Take 2 different observers, 
one that is moving beside the ship at the same velocity as it has prior to 
activating the drive.  The second one is moving at a velocity that allows him 
to 
observe the ship decelerate first until it reaches a velocity of zero relative 
to him and then to accelerate in the reverse direction until it reaches the 
exact same original velocity in the opposite direction.
>
>The first observer sees the velocity of the ship go from for this example 0 
meters per second to 2 meters per second.  He determines that the ship now has 
2*2*Mass/2 units of kinetic energy.  The amount of internal mass that the ship 
burns up to achieve this acceleration is extremely small and can almost be 
neglected.
>
>The second observer sees the ship moving at the same speed before and then 
after the application of the drive.   The only difference he measures is that 
the direction of the motion of the ship is reversed by the drive.  So he sees 
the ship begin the motion moving 1 meter per second relative to him initially 
and  then after the drive shuts down the ship is moving 1 meter per second in 
the opposite direction.   This observer determines that the kinetic energy of 
the ship has not changed measurably due to the application of the drive.
>
>At this low velocity the second observer determines that the mass converted 
into drive power is essentially the same as that determined by the first 
observer.  Both guys have a very hard time figuring out exactly how much mass 
is 
converted, and they agree that any difference is hidden in the noise.
>
>In this experiment we have two independent observers seeing the same ship 
>being 
subject to the same drive.  The amount of kinetic energy being deposited to the 
ship by essentially the same loss of internal mass varies remarkably according 
to each.  This does not add up.
>
>As I have mentioned before, with a normal drive this case can be handled 
without a problem.   The exhaust material supplies the kinetic energy and 
momentum needed to balance the equation.  
>
>Apparently every observer moving at a different initial velocity relative to 
the driven ship arrives at a significantly different calculation regarding the 
ships energy balance after the application of the drive.  How could something 
this radical be possible?  Let me say it again, there is no problem of this 
sort 
to deal with when a standard drive is applied.
>
>Dave
>
Regards,

Robin van Spaandonk

http://rvanspaa.freehostia.com/project.html


 

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