# Modifying Newton's First Law of Motion

Discussion in 'Alternative Theories' started by hansda, Jun 8, 2017.

1. ### DaveC426913Valued Senior Member

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This is false. Relativistic contraction does not result in any compressive force. Nor strain, nor stress.

3. ### hansdaValued Senior Member

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With relativistic contraction, isn't it a physical length contraction?

What is your idea of strain, in Newtonian Model of Physics?

5. ### DaveC426913Valued Senior Member

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It is. It is the contraction of everything. The very atoms will be contracted in the direction of travel*, as will the spaces between them. So there is no strain involved.

*Yes, to an external observer, the atoms of spaceship - and its occupants - will all appear as smarties - flattened spheres:

(Remember, this only occurs from an external observer's frame of reference. The occupants of the spaceship experience no contraction, nor do any of its parts.)

There is no such thing as relativistic contraction in Newtonian physics.
Newtonian physics would (naively) predict that a spaceship could accelerate past c and on to infinity, with no untoward effects.

That's why it's been supplanted by Einsteinian physics.
Newtonian physics can only apply at non-relativistic velocities (and gravities).

Last edited: Aug 24, 2017

7. ### originTrump is the best argument against a democracy.Valued Senior Member

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Strain is the amount of deformation of a material from a stress (force).
This has nothing to due with length contraction since the contraction is not due to a force.

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Yeah, this was hanging me up: as I understand it, the 'shortening' requires a 'locality,' a frame of reference external to the frame being observed.

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The Lorentz Transformation (as I understand them) require the invariance of the speed of light, which is diametrically opposed to your Instantaneous Law of Inertia, which can (unless I misunderstand) only hold true in a discrete or discontinuous or discrete time vector. If time is composed of discrete 'quanta' then 'c' cannot be invariant. It must in this scenario constantly oscillate between '0' & 'c'.

10. ### originTrump is the best argument against a democracy.Valued Senior Member

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No matter how fast someone goes by you or how fast you go by someone, you will never feel 'squished' nor will time seem to pass abnormally.

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Don't believe I said anything about 'squished.' In fact, I was saying quite the opposite.

12. ### DaveC426913Valued Senior Member

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Shortening/squished. Same in my books.

13. ### originTrump is the best argument against a democracy.Valued Senior Member

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I must have misunderstood.
When you said this:
I thought you were having trouble with the inertial frames.

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No problem.

15. ### hansdaValued Senior Member

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What is the formula/equation, used for calculating strain?

16. ### hansdaValued Senior Member

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This wiki article is contradictory to your views. https://en.wikipedia.org/wiki/Length_contraction . Here the length contraction is physical.

17. ### originTrump is the best argument against a democracy.Valued Senior Member

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That is a pretty surprising question coming from someone who claims to have the 'holy grail' theory of physics!

$\epsilon = \frac{dl}{l_0}$

18. ### hansdaValued Senior Member

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For length shortenning, you can see this wiki article https://en.wikipedia.org/wiki/Length_contraction . Length shortenning depends on Lorentz factor which depends on the relativistic speed(relative velocity between the observer and the moving object).

19. ### hansdaValued Senior Member

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Good. So, Lorentz Length Contraction can fit in this definition of strain.

20. ### originTrump is the best argument against a democracy.Valued Senior Member

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The problem is that you did not understand his reply and you only have a colloquial understanding of physics.

You said:
If there is measurable length contraction due to relativistic speed; there will be measurable strain. Strain is related with stress. Stress is related with force. So, "relativistic length contraction" can be related with "compressive force".

There is no strain with length contraction. Strain is a change in length of a sample due to a force. There is no force applied in length contraction.
The length contraction is completely different than a deformation due to a force. With length contraction the ENTIRE reference frame is contracted not just the materials in the frame - the frame itself is contracted. This is fairly subtle so I do not expect you to understand it (I hope you do though).

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22. ### DaveC426913Valued Senior Member

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The Wiki article in no way contradicts my post.
Length contraction is a real phenomemon, manifest by a difference in velocity of frames of reference between observers and observed.

I think what you forget is the "relative" part of relativity.

Two observers flying past each other in space is a symmetrical scenario. There is no meaning to saying which one is stationary and which one is moving.

Spaceship 'Eastward Ho' is at rest in its own reference frame. It experiences no length contraction itself.
Eastward Ho observes Spaceship 'Westward Ho' whiz past at .99c. Westward Ho is observed to be length contracted.

...at the very same time as...

Spaceship 'Westward Ho' is at rest in its own reference frame. It experiences no length contraction itself.
Westward Ho observes Spaceship 'Eastward Ho' whiz past at .99c. Eastward Ho is observed to be length contracted.

Your suggestion that Eastward Ho both experiences a compressive force - and simultaneously does not experience a compressive force - is self-contradictory.

23. ### hansdaValued Senior Member

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Seems you are not able to come out of your GR obsession. Natural events happen naturally. They dont know GR, Newtonian Model, QM, QG or any other models for interpreting these natural events. All these different models have their own distinctive characteristics. In GR, there is no concept of force. But in Newtonian Model, force is very basic concept.

Here the natural event is that, if an object travels at relativistic speed its length will contract in the direction of its travel.

This natural event can be explained through GR. This natural event also can be explained through Newtonian Model. If it is explained through GR, obviously no force can be seen. But if this event is to be explained through Newtonian Model, a force has to be considered.