Re: DANGER: Mass-Independent Drive...
In reply to #1235 DANGER: Mass-Independent Drive Is Perpetual Motion Machine by Bart Massey
Bart Massey writes: >> ...the way an MT manuver drive works is counterintuitive (ie only volume is >> important, not mass). In any drive that depends on mass, this won't work >> well... >Aiigh. I don't know my Traveller well enough to comment very authoritatively, >but if the above statement is true, a Traveller perpetual motion machine >(i.e. an infinite energy source) exists. Yup, it sure does. However, you don't need mass-independence to get energy; All the is required is that the drive is reactionless. I worked through the equations, and it turns out that any drive that violates Newton's 3rd law (action/reaction) will *automatically* violate conservation of energy. Here's why: (anyone who doesn't want the gory details, skip the rest) Say we have a ship that masses 1500 tons, and requires 280 MW to accelerate at 1g. After T seconds of accelleration in one direction, the energy expended will be 2.8e8*T joules, and the kinetic energy of the ship will be 1/2 MV^2 = 0.5 * 1.5e6*(9.8*T)^2 = ~7.2e7 * T^2 joules. This means energy in is linear in T, while energy of the ship is quadratic in T; so only at one value of T will they be equal, and by choosing sufficiently large T ( in this case more than about 4 seconds) the ship has more KE than energy put in. My perpetual motion machine design is 2 sets of reverse linear accellerators on an airless world, about 1000 km apart. The ship runs on batteries, and it accellerates to ~4 km/sec then cruises through the hoops, decellerating magnetically, and in the process generating electrical energy, which is stored. After the ship is stopped, it recharges its batteries with a fraction of the energy it just generated and heads back towards the other set of hoops. Result: Lots of free electric power. (HLG Inc., Patent Pending) Of course, the energy-producing Megacorps either squelch this or have a monopoly on it, so you still have to pay for power :-) I always have had fun figuring this sort of stuff out to bug the GM with, especially since he is a physicist :-) He is smart tho and usually says "OK, if you're so bright, figure out why everyone isn't doing it..." W. Dow Rieder When the only tool you have is a hammer, all your problems start to look like nails...