Can Reactionless Drive be Possible?

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In summary: So the theory is not correct. There is no net force on the system that propels it forward or backwards.The forces which *do* cause a net force on the system are the EM waves and those waves propagate at the speed of light. In the low frequency limit they can be approximated by the instantaneous Coulomb force, but that is not applicable here because the fields are changing rapidly. Instead we must use Maxwell's equations with the appropriate boundary conditions. The net force on the system will be the integral of the Poynting vector over an appropriate surface. That Poynting vector will be very small as a result of the fields being nearly parallel to the surface, so the net force will
  • #1
Kasko32
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Is this possible?

Inertial propulsion.

If we take that nothing is faster than speed of light than we can take that reaction of force through matter can not be faster than c.

If one body act on other body by force, than other body react with same amount of force to the first body.

https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/1017601_10201279962618692_1778939648_n.jpg

Lets take that in our system second body rotate certain speed around its axis.
Example will be housing with rotating disc. Magnets will provide force. Every full circle magnets will push disc up according to housing.

https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-ash4/999308_10201279962698694_2034001389_n.jpg

Disc rotate, so force on axis will not be in same direction as forces applied in first position

https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-prn1/1009916_10201279962538690_1502604373_n.jpg

At this point we don`t have forces witch are in 180 degree opposite direction.
We have force that push down and second one that push housing up through axis in certain angle. Because of angle we have resultant force Fr applied.

https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-prn1/1013931_10201279962818697_1789739154_n.jpg

For example

disc rotation speed 1 000 000 rpm, which is 104 666,66 rad/s
r=10 m

we have time t1 when magnet act with force on rim of disc
we have second time t2 which is 3,34 e-8 s when force acts on axis of disc
difference between t1 and t2 is 0,003495 rad which is 0,2 degreehousing push against the disc in t1 and reaction to the axis happened at t2 time and act on housing in 0,2 degree
 
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  • #2
Your links are incomplete. Please correct them.
 
  • #3
Without functioning links it is not possible to tell, however a device with spinning magnets will generate EM waves and those EM waves will contain a small amount of momentum. That small amount of momentum can, in principle, propel the device. It is not reactionless, it uses the momentum of EM waves.

Of course, such a device will be horribly inefficient, like using a rocket with no nozzle and just hoping that a little more exhaust goes one way rather than the other. You will be much better off simply shining a laser off the back.

Other than the very small amount of EM momentum there will be no net force on the device. Specifically, the internal stresses and strains that you seem to think will provide propulsion will not. Any propulsion will be purely due to asymmetric radiation of EM waves.
 
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  • #4
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  • #5
Oh I see now. You are suggesting a force applied at the circumference takes time to propagate to the axle and in that time the disc has rotated.
 
  • #6
CWatters said:
Oh I see now. You are suggesting a force applied at the circumference takes time to propagate to the axle and in that time the disc has rotated.

Yes, that is idea. I see there is no practical usage, just wondering if this theory is correct.
 
  • #7
Well no it can't be correct because the laws of physics say you can't build a reactionless drive. It's one of those situations where it's not obvious (at least to me) where the problem is but there will be one somewhere. The question is really is it worth spending time on it?

My thinking is that you haven't considered all the forces involved in the initial "collision" between the magnets. For example it's not obvious to me that the initial forces are radial.
 
  • #8
Kasko32 said:
Yes, that is idea. I see there is no practical usage, just wondering if this theory is correct.
The stresses and strains which propagate at the speed of sound do not cause any net force on the system at any time.
 

Related to Can Reactionless Drive be Possible?

1. What is a reactionless drive?

A reactionless drive, also known as a reactionless propulsion system, is a hypothetical device that would allow for propulsion without the need for a reaction mass. It violates Newton's third law of motion, which states that for every action, there is an equal and opposite reaction.

2. Is it possible to create a reactionless drive?

As of now, there is no known scientific principle or technology that would allow for the creation of a reactionless drive. All propulsion systems currently in use rely on the principle of action and reaction. However, there are ongoing research and theories around the concept, but there is no concrete evidence to suggest that it is possible.

3. Why is a reactionless drive considered impossible?

The concept of a reactionless drive goes against the fundamental laws of physics, including the conservation of momentum and energy. It would require creating a force without any corresponding action, which is not possible according to our current understanding of physics.

4. Are there any proposed explanations for a reactionless drive?

Some proposed explanations for a reactionless drive include manipulating the curvature of space-time or harnessing zero-point energy. However, these theories are still speculative and have not been proven to be possible.

5. What are the potential implications of a reactionless drive?

If a reactionless drive were to be created, it could revolutionize space exploration and transportation. It could make interstellar travel possible and significantly reduce the cost and time of space missions. However, the creation of a reactionless drive would require a complete paradigm shift in our understanding of physics, which is currently not supported by scientific evidence.

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