In reply to David Roberson's message of Mon, 14 Mar 2016 20:49:21 -0400: Hi, [snip] >The problem would show up if the space ship then reversed his maneuver and >returned back to that original frame. Both people would again calculate >approximately the same mass conversion that occurs due to the force >generation. So at the end of the trip, the ship would be depleted of some of >its mass for no net apparent change in velocity or position. Where did the >energy go?
Perhaps like a car with regenerative braking, it's also possible to reverse the process and store energy? Try replacing the EM drive vehicle with a perfectly efficient (i.e. loss-less for the sake of argument) electric car. It starts off expending energy to reach some speed in a given direction. Coasts the rest of the way around the planet, until approaching it's starting point where the regenerative braking kicks in and slows it to halt at exactly it's starting point with the batteries perfectly recharged. Nothing lost, nothing gained, nothing changed. In a car with no regenerative breaking, the energy shows up as heat during breaking, and the batteries don't get recharged. A different point of view:- Take an electric car that is traveling at 100 mph with respect to the road, however in it's own frame of reference, the car is standing still. Now the driver suddenly applies the breaks, and they get hot. Where did the energy come from to heat the breaks? Obviously from the road which is rushing past at 100 mph, until enough energy has been placed into the breaks by the road to "accelerate" the car to the same velocity as the road. This sounds ridiculous, but from the point of view of the driver, it's exactly what happens. In a car with regenerative breaking, the batteries get recharged instead of heat being created, which is kind of convenient. You apply the breaks and the universe places energy in your batteries. Now imagine a road that is invisible, so that you can't see how fast you are traveling relative to the road, or in which direction..... :) BTW as an extra thing to think about:- There *is* a special, frame of reference; one's own frame, in which one is, by definition, always stationary, and hence it's a completely useless frame of reference. Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
