What's Wrong With This System?

[Greg_G47]

I'm wondering what's wrong with this proposal for a 'reactionless drive' mechanism. I'm certain there's probably some error (I'm pretty sure a reactionless drive is an error by definition) but can't figure out what it is.

 

 

1)accelerate a beam of charged particles (ex: electrons) on a circular path using electrical/magnetic fields, such that their relativistic mass is increased.

 

2) impart an orthogonal component to the motion of the beam, so it follows a helical path.

 

3) slow the radial velocity of the beam, leaving its axial component alone, causing the relativistic mass to decrease.

 

4) reduce the axial velocity of the beam, then arrest its axial motion. the now-lighter particles should take less force to decelerate axially than they took to accelerate.

 

5) recirculate the particles to their origin.

 

Since the mass or particles being accelerated in one axial direction is greater than the mass of particles being accelerated in the other, and the acceleration/deceleration that appreciably affects the mass of the particles is not along the axial vector, it looks like there is a net force on the entire system in one direction.

 

There's a patent pending for something similar, which is why I'm curious.

 

Despite the title, I can't see any reason why such a contraption could exceed the speed of light. There's nothing special about it that allows it to violate the laws of the universe.

 

However, I can't locate anything that prevents the device from accelerating at all. I'm guessing the issue comes from a first-year-university perspective on relativistic mass and momentum, but I can't pin it down. any clarification is appreciated. try to keep the math at 2nd-year-uni calculus or lower, as that's where I stopped taking math courses .

[Pyrotex]

Hmmm.

Very interesting.

I'll get back to you on this.

[Greg_G47]

*bump*

[maddog]

I'm wondering what's wrong with this proposal for a 'reactionless drive' mechanism. I'm certain there's probably some error (I'm pretty sure a reactionless drive is an error by definition) but can't figure out what it is.

 

 

1)accelerate a beam of charged particles (ex: electrons) on a circular path using electrical/magnetic fields, such that their relativistic mass is increased.

 

2) impart an orthogonal component to the motion of the beam, so it follows a helical path.

 

3) slow the radial velocity of the beam, leaving its axial component alone, causing the relativistic mass to decrease.

 

4) reduce the axial velocity of the beam, then arrest its axial motion. the now-lighter particles should take less force to decelerate axially than they took to accelerate.

 

5) recirculate the particles to their origin.

 

Since the mass or particles being accelerated in one axial direction is greater than the mass of particles being accelerated in the other, and the acceleration/deceleration that appreciably affects the mass of the particles is not along the axial vector, it looks like there is a net force on the entire system in one direction.

`

There's a patent pending for something similar, which is why I'm curious.

http://www.google.com/patents?id=VvOCAAAAEBAJ&dq="faster+than+light"

 

Despite the title, I can't see any reason why such a contraption could exceed the speed of light. There's nothing special about it that allows it to violate the laws of the universe.

Special Relativity prevents any such device (were it to propel at all) from

moving FTL. Your particles (electrons) may be accelerated relativistic,

though this does not mean any such craft attached will move at those

speeds. Momentum is a product of mass * velocity (mv). The total mass

is the sum of all parts. If some parts get relativistically heavier, more work

must be done to overcome inertia to move the craft.

 

However, I can't locate anything that prevents the device from accelerating at all. I'm guessing the issue comes from a first-year-university perspective on relativistic mass and momentum, but I can't pin it down. any clarification is appreciated. try to keep the math at 2nd-year-uni calculus or lower, as that's where I stopped taking math courses :).

I will have to create a picture (or go lookup the patent) to see if this

would propel anything at all. I am open, though skeptical. :)

 

maddog

[modest]

I don't see a momentum conservation problem here. The device should start and stop without acceleration by my reasoning. I'm not sure where you're thinking is different, but it might be here:

 

3) slow the radial velocity of the beam, leaving its axial component alone, causing the relativistic mass to decrease.

 

Accomplishing this would require transferring momentum along the 'axial' axis. In other words: doing this would require accelerating the drive axially as well as radially. When this is considered, I believe step 2 and 3 would accelerate the drive in one axial direction while step 4 and 4.5 (step 4 has 2 parts which are the reciprocal of 2 and 3) would accelerate the drive equally in the other axial directing resulting in conservation of momentum.

 

~modest

[Greg_G47]

It definitely doesn't work. The transverse mass (relative to each particle's tangential velocity down the helical axis) doesn't change by increasing the angular velocity. That is, the particles get heavier, but not in the axial direction.

 

The result: the beam takes more force/energy to rotate it at relativistic speeds but is no more difficult to "push" orthogonally to the rotation than it would be to push the particles at rest. Since there's no difference between the force exerted to push or revover the particles, all we have is another debunked "stiction" drive.

 

Hope someone told the patent owner....

 

Thanks for your help with this!

 

-Greg

[maddog]

I agree with both of you. I don't see this causing any induced translation in

position. No propogation. Not going anywhere.

 

maddog

[CraigD]

The transverse mass (relative to each particle's tangential velocity down the helical axis) doesn't change by increasing the angular velocity. That is, the particles get heavier, but not in the axial direction.

I don’t think this explanation is correct. Although the force [imath]F_y[/imath] that produces an acceleration [imath]a_y[/imath] in a direction orthogonal to a moving body (the spinning charged particles in Dale Retter’s invention) is less than a force [imath]F_x[/imath] that produces a parallel acceleration [imath]a_x[/imath], it does increase as the velocity of the body, whether linear or circular, per the usual Lorenz factor (see section “special relativity” of the wikipedia article “force”).

 

The heart of Retter’s this claim is the claim that mass dilation allows violation of the law of conservation of momentum. It’s easy to see how one might reach this conclusion, via reasoning something like this (for simplicity, I’ll dispense with Retter’s high speed charged particles, and imagine ordinary machine parts):

1. Enclose a couple of counter rotating, motor-drive wheels in a sturdy box
   
2. Attach the box to another box – let’s call it the cab - with some sort of linear actuator (eg: a hydraulic piston).
   
3. Spin the wheels. Because they are counter rotating, the wheel box is subject to no net force. Due to mass dilation, the box and it’s contents mass more - call the difference [imath]M_{\mbox{wheels} 1} - M_{\mbox{wheels} 0}[/imath].
   
4. Push the cab and the wheel box apart – ie: exert a force between them. The outsides of the two boxes now have velocities [imath]M_{\mbox{cab}} V_{\mbox{cab}} + M_{\mbox{wheels}\, 1}V_{\mbox{wheels}} = 0[/imath]
   
5. Stop spinning the wheels. Again, the wheel box has no net force, and its mass is now [imath]M_{\mbox{wheels}\, 0}[/imath]
   
6. Pull the bad and wheel box together – exert a force until the distance between them is not changing. The velocity of the two boxes should now be
   [math]\frac{ (M_{\mbox{wheels}\, 1} - M_{\mbox{wheels}\, 0})V_{\mbox{wheels}}}{M_{\mbox{cab}} + M_{\mbox{wheels}\, 0}}[/math]
   

Step 5 is where conservation of momentum is violated.

 

In essence, this system should be equivalent to one in which the wheel box is replaced by a box that ejects some mass in step 5. Such a system is simply a rocket, where the ejected mass is its exhaust.

 

Where this reasoning errs is in ignoring that steps 3 and 5 involve mechanical work, so require energy. Because according to special relativity, mass and energy are equivalent per [imath]E = Mc^2[/imath], unless the wheel box gets outside energy, it will lose exactly the same mass spinning up its wheels as the wheels gain in mass. If it does get outside energy (from the only other part of the system, the cab), that’s a transfer of momentum between the two boxes. In either case, unless the system gains or loses mass or energy, its momentum won’t change.

 

The though experiment above can be made even simpler by just considering 2 bodies in relative motion subject to equal and opposite forces. Only if we exclude energy from our calculations – ie: assume that the system can do work with nothing – can we show it violating conservation of momentum.