Good work fellows however I am more inclined to look at useable
interplanetary speeds, earth to Mars in a few weeks or so, say
~518041367424 km in 6 weeks [1008 hours ] This requires hideous
velocities and you will need a hell of a bumperbar on you ship. How do
the numbers come out?
Kyle R. Mcallister wrote:
----- Original Message ----- From: John Berry
To: vortex-l@eskimo.com
Sent: Friday, September 15, 2006 6:27 AM
Subject: Re: [Vo]: stationary emdrive- inertial anchor
What you should note is that this device if it works at all MUST
violate the conservation of energy, there is no way round it, if you
use it to accelerate or row for >10 seconds and it accelerated it to
1 meter a second using .5KWh say, then if you run it for 20 seconds
you'd have used 1KWh, have 2 meters a second velocity >but the energy
contained in forward movement of your ship is 4 times that of running
the engines for the 10 seconds.
No.
Assume a 1000kg spacecraft at initially velocity 0m/s. (we will ignore
the "relatives" here for now, more on this later)
Assume that this spacecraft uses its reactionless propulsion system
(whatever it may be) to accelerate to approximately v=0.1c, or
29,979,246 m/s. We will ignore relativistic effects at this time. The
energy require to get to this velocity will be K = 1/2 m v^2, or in
this case, 4.494x10^17J. Not a small amount. But what is the energy
required then to accelerate the craft to only v=0.05c? 1.123x10^17J,
or 25% of that required to reach 0.1c. Now of course this makes sense,
the square of velocity and all that. What it also indicates is that to
go from v=0c to v=0.1c you must use increasing energy as time goes by.
If you use a constant energy per unit time (I am using only basic
units here to avoid confusion) you will find your acceleration tapers
off rapidly as velocity is increased.
So, if you use say (changing from kWh to something that is easier to
follow, kW) 0.5kW for 10 seconds, on a 10,000kg object, the kinetic
energy gained by the object is 5kJ, and our object is moving at a
gentle 1m/s. This of course assumes that your method of converting
electrical energy input to kinetic energy is 100% efficient.
But...if we apply 0.5kW for 20 seconds, we have added 10kJ to our
10,000kg object, and its velocity is now...only 1.414m/sec. Can you
get to 0.1c with a constant-power drive? Absolutely, but it will take
much longer to get there, and efficiency will drop as speed increases,
and fall rapidly the faster you try to go. If on the other hand, you
use a constant-acceleration approach, you get there (to your desired
speed) much faster, but you use an ever increasing amount of power.
The total energy to reach 0.1c for constant-power or
constant-acceleration is the same.
Now here's something interesting. If drive efficiency in attaining
some velocity from some given energy input decreases like this over
time, as velocity builds up, it would seem to imply that an absolute
velocity is important. A very big no-no when it comes to relativity as
we know it. (or as we like to know it)
You can have a reactionless drive which conserves energy globally, but
to do this it will demonstrate some rather odd effects (at first
glance) which later once you have juggled it in your mind for a while,
really don't end up so confusing in the end. But it does seem to lead
to one reference frame being preferred, and acting as the "road" for
your hypothesized "space car". If a reactionless drive is constructed
successfully, one wonders about its uses to test relativity in a new
and unique way. I'll let you think on that for a bit.
--Kyle