Post by: jeffreyH on 23/03/2018 12:42:52
Post by: Colin2B on 23/03/2018 14:47:41
Post by: jeffreyH on 23/03/2018 15:17:38
Post by: Colin2B on 23/03/2018 17:30:00
Post by: jeffreyH on 23/03/2018 18:17:06
Are you thinking of something other than, dare I say it, relativistic mass?
Well the Lorentz factor is real as demonstrated by time dilation. The question is which side of the equation does it belong on when determining force? You could argue that it makes no difference as it is unitless.
Post by: jeffreyH on 23/03/2018 18:26:48
Post by: jeffreyH on 23/03/2018 19:13:45
Where F is force, p is momentum and t is time. The Lorentz factor is applied to the force in a frame moving relative to an inertial observer. This requires no function to be applied to momentum.
Post by: jeffreyH on 24/03/2018 12:45:28
This conclusion is arrived at by showing that the equation is homogeneous.
Post by: jeffreyH on 24/03/2018 13:00:49
Post by: geordief on 24/03/2018 13:06:03
The speed would make a difference inasmuch as there is a difference between a circular and elliptical orbit due to a difference in velocity. So the effect of the field is affected by relative velocity. The above implies an effect on force carriers due to an increasing velocity. This is the root of time dilation.By "force carriers" do you mean gravitons?
Post by: jeffreyH on 24/03/2018 13:09:14
Post by: jeffreyH on 24/03/2018 13:27:03
Post by: geordief on 24/03/2018 13:29:32
. Why do things continue to move in a straight line at constant velocity? Is this connected to the speed of light? What are the mathematics that would show this? Just a few topics for conversation.
If there is any predictability at all in physics then one ongoing measurement must surely be the same as the previous one if conditions are unchanged.**
That defines a straight line perhaps .which can be a curved line provided the curvature is constant.
So a straight line can be seen as analogous to logical reasoning. No straight lines ,no reliable mental
constructs possible..
Of course if our collective mental constructs are somehow flawed at "base camp" then our understanding of our surroundings also start with that handicap.
But I think we can believe (a faith?) that our mental constructs and our physical environment are "joined at the hip" even if the union is obscured from our understanding.
I have no idea what mathematics might be brought to bear on my assertions(or if they have any merit) but "straight lines" is an interesting topic.
**edit: on reflection that is certainly not irrefutable
Post by: opportunity on 24/03/2018 13:33:08
As things become more complex you run into the n-body problem. This applies to much more than elementary particles.
Really? The n-body problem is pitched at celestial objects resolving GR and SR issues. That's like saying ice cream is cold. How do things become more complex than the elementary particle level there? Wouldn't you want to solve the elementary particle level first?
Post by: jeffreyH on 24/03/2018 13:38:43
@geordief I think you need to clarify your thoughts. I would have a look at classical mechanics and Newton's laws.
Post by: jeffreyH on 24/03/2018 13:50:58
Post by: geordief on 24/03/2018 13:51:41
You mean my thoughts should be more focused here?
@geordief I think you need to clarify your thoughts. I would have a look at classical mechanics and Newton's laws.
Is your question about straight lines restricted to classical physics (are there any straight lines in quantum physics?)
Post by: jeffreyH on 24/03/2018 14:11:37
. Why do things continue to move in a straight line at constant velocity? Is this connected to the speed of light? What are the mathematics that would show this? Just a few topics for conversation.
Quote
If there is any predictability at all in physics then one ongoing measurement must surely be the same as the previous one if conditions are unchanged.**This may be true at the microscopic scale and in quantum mechanics but at macroscopic scales relative motion has to be taken into account.
Quote
That defines a straight line perhaps .which can be a curved line provided the curvature is constant.I can see why you are considering curvature as representing a straight line since this describes the way geodesics relate to geometry. The second sentence isn't clear.
So a straight line can be seen as analogous to logical reasoning. No straight lines ,no reliable mental
constructs possible..
Quote
Of course if our collective mental constructs are somehow flawed at "base camp" then our understanding of our surroundings also start with that handicap.I have no idea what you mean here. At least not in scientific terms.
But I think we can believe (a faith?) that our mental constructs and our physical environment are "joined at the hip" even if the union is obscured from our understanding.
Quote
I have no idea what mathematics might be brought to bear on my assertions(or if they have any merit) but "straight lines" is an interesting topic.
**edit: on reflection that is certainly not irrefutable
Post by: opportunity on 24/03/2018 14:17:05
Post by: geordief on 24/03/2018 14:29:02
The quote function has defeated me this time and so I will still try to answer as best I can.
I felt ,in contradiction to you that straight lines should apply more to classical physics than quantum physics.
Also to your quote "The second sentence isn't clear." I was meandering from the question but ,in that a straight line can be seen as one (unit) step followed by another then there is a superficial similarity to steps in logic. But this was probably not particularly helpful or useful .
Actually my initial thought regarding straight lines was to bring up extremal aging but I have yet to understand that concept very well and so steered clear of parading this additional aspect of my ignorance. ;)
Post by: jeffreyH on 24/03/2018 14:32:06
Post by: opportunity on 24/03/2018 14:40:29
Really?
Post by: jeffreyH on 24/03/2018 15:06:46
https://www.physicsforums.com/threads/principle-of-extremal-aging.573440/
Post by: jeffreyH on 24/03/2018 15:09:12
....and the "family" of elementary particles still has no gravitational effect?
Really?
Negligible is not synonymous with nonexistent.
Post by: jeffreyH on 24/03/2018 15:37:05
Post by: jeffreyH on 24/03/2018 15:43:39
Are you serious? You're drawing a line between negligible and non-existant...
So you don't then? Then you don't care about precision of language. If you cannot define what you mean the others won't understand it. That makes everything you say irrelevant.
Post by: jeffreyH on 24/03/2018 15:46:08
Post by: jeffreyH on 24/03/2018 15:47:54
https://www.amazon.co.uk/Introduction-Elementary-Particles-David-Griffiths/dp/3527406018
Post by: jeffreyH on 24/03/2018 16:12:46
Post by: jeffreyH on 24/03/2018 16:48:17
If x0 is the initial position of an object then x = x0 + vt is the position of an object at time t.
If the velocity were v - ε then its position at time t would be
x0 + (v - ε)t = x0 + vt - εt = x - εt
We can represent a velocity as
where P is the momentum matrix. Nowhere is gravity taken into consideration.
Post by: jeffreyH on 24/03/2018 16:49:17
Post by: jeffreyH on 24/03/2018 17:01:10
I had to learn linear algebra before that made sense.
Post by: jeffreyH on 24/03/2018 17:10:40
Post by: jeffreyH on 24/03/2018 17:46:03
Am I wrong in saying if something is going fast enough, "why not" (I'm focussing on the question of the post here, nouns, verbs, and adjectives)?
This is an interesting point. Not because gravity may accumulate at speed but that it has to be affected by time dilation just like all other forces.
Quote
It can be "a" source accoring to SR and GR, yet as stand-alone mass, as kinetic energy, and I am thinking that's your question, stationary mass, is that kinetic, right? It may not be visible, but "actual" on an elementary particle level.
The above is wrong.
Post by: jeffreyH on 24/03/2018 18:02:00
Post by: jeffreyH on 24/03/2018 18:21:33
https://en.wikipedia.org/wiki/Gauge_boson
Post by: jeffreyH on 24/03/2018 19:14:10
http://www.sciencebits.com/node/175
This should be taken into account.
Post by: jeffreyH on 24/03/2018 19:49:41
Post by: jeffreyH on 24/03/2018 19:54:47
Post by: jeffreyH on 24/03/2018 20:17:25
https://www.researchgate.net/publication/254235022_Derivations_of_Relativistic_Force_Transformation_Equations
Post by: Colin2B on 25/03/2018 23:17:15
I am not convinced about the veracity of the above equation.Now much of the deadwood has been pruned it’s easier to see the trees.
Question I have about this
is what do you do about 
which changes with velocity and hence with time so do you need to include 
on the rhs ?
Post by: jeffreyH on 26/03/2018 10:09:20
Post by: jeffreyH on 26/03/2018 12:42:46
I am not convinced about the veracity of the above equation.Now much of the deadwood has been pruned it’s easier to see the trees.
Question I have about this
That results in
which can be rearranged as 
. Now we are into homogeneous first order differential equation territory.
Post by: jeffreyH on 26/03/2018 12:48:15
Post by: PmbPhy on 26/03/2018 13:04:09
I think not but it would be interesting to get other views on the subject.Yes. All forms of energy can create a gravitational field. Its whatever the T^00 component of the stress-energy-momentum consists of. Didn't I ever mention that the energy of a photon or a directed beam of light is all kinetic energy and that light can create a gravitational field? This was done way back in 1931 by Tolman, Ehrenfest and Podolsky in the article
On The Gravitational Field Produced by Light, Tolman, Ehrenfest and Podolsky, Physical Review, Vol. (37), March 1, 1931, pg 602-615.
I placed it online in my own words at:
http://www.newenglandphysics.org/physics_world/gr/grav_light.htm
Post by: jeffreyH on 26/03/2018 17:17:54
Post by: jeffreyH on 26/03/2018 18:10:13
Post by: jeffreyH on 26/03/2018 18:17:03
Post by: jeffreyH on 26/03/2018 18:34:17
Post by: jeffreyH on 26/03/2018 18:37:05
Post by: Colin2B on 26/03/2018 18:52:34
That results inWhat I was thinking was to move
from under F and move it to rhs So -
What do you think?
Post by: jeffreyH on 26/03/2018 19:19:13
That results inWhat I was thinking was to move
So -
What do you think?
I can give that a go.
Post by: jeffreyH on 26/03/2018 20:06:00
Post by: jeffreyH on 26/03/2018 20:55:48
https://www.physicsforums.com/threads/differentiating-lorentz-factor-with-respect-to-time.153702/
Post by: Colin2B on 26/03/2018 22:57:21
Try
Post by: jeffreyH on 30/03/2018 16:13:14
Post by: jeffreyH on 30/03/2018 17:05:05
Post by: jeffreyH on 30/03/2018 17:14:05
https://en.wikipedia.org/wiki/Mass_flow_rate
Post by: jeffreyH on 30/03/2018 17:21:12
Post by: jeffreyH on 31/03/2018 11:29:27