Kyle Mcallister wrote: > --- [email protected] wrote: > > >> Since a = f/m, and m is constant, if there is a >> force in one direction only, >> then that force should accelerate the mass while it >> operates. That acceleration >> should increase the speed, which should then remain >> constant until the next >> acceleration pulse. IOW the speed should increase in >> steps. > > It may be that there is a way to make it accelerate. I > don't know. But what Laithwaite/Dawson say, and as far > as I can tell, what happens in their setup is this: > > 1. Mass M is moved say 10 units to the right by > precession, thus (supposedly) forcelessly. F=0 at this > point.
This is a neat trick. If you can do this you've already shattered Newton's laws, no need to go any farther. Note that the center of gravity of a top or gyroscope does not move "forcelessly" as a result of precession, not with a conventional gyro operating with conventional physics, anyway. There's a lateral force on the support which is equal and opposite to the force needed to accelerate the center of mass as it precesses. Of course, when the Earth precesses, it does it without any "support" -- but in fact it also does it without shifting its center of mass. Rather, the axis of rotation shifts, while leaving the Earth's center of mass traveling uniformly along its orbital path. (Furthermore, if you took the Sun and Moon out of the picture the Earth wouldn't precess. The external force acting on it is necessary to make the precession "go".) > 2. M is moved back to the left, to the starting point > inertially. As it accelerates, the trolley moves to > the right, say, ultimately 2 units. Velocity of the > entire system is towards the right. > 3. When M reaches the starting point, it is stopped, > decelerating, thus cancelling the previous > acceleration. The velocity is now zero again, but the > trolley is 2 units to the right. > 4. Repeat. > > Each cycle, the velocity ends as zero, but a 'net' > constant velocity is attained based on the > acceleration imparted to M, and its mass ratio versus > the rest of the trolley. As far as I see, there is not > a net gain in velocity over time, so no additive > acceleration. You get 'displacement' over time, > however, each cycle moving the trolley's center of > mass 2 units to the right. Assuming, of course, that > it does work. I don't know if it does or not. > > --Kyle > > > >
