Physics Help Forum Fictitious force is not conserved.

 Special and General Relativity Special and General Relativity Physics Help Forum

Jan 15th 2018, 10:12 PM   #11

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 Originally Posted by avito009 Just listen to me carefully you will understand the purpose of defining gravity to not be conserved. Reasoning is simple observe when you throw an object in air verically it falls down with a constant acceleration 9.8 m/s^2. This means the pull of gravity is stronger close to the earth which proves gravity is not conserved.
We don't even need GR here. The gravitational force in Newtonian gravity is defined by
$\displaystyle F = \frac{Gm_1m_2}{r^2}$

It is only near the surface of the Earth that we can say that the acceleration due to gravity is essentially constant. And, as the Newtonian model suggests, the force between two masses gets larger the closer the two masses become. And Newtonian gravity can be easily shown to be a conservative force. I don't understand your point about this.

 Originally Posted by avito009 This is the basis for the new theory I am proposing. In brief i would prove that light cant be pulled inside the black hole because there cant be acceleration because nothing travels faster than the speed of light. Since there is no acceleration if light is pulled inside the black hole it would mean gravity is conserved since the pull of gravity would be uniform and the pull would not be greater at the bottom.
See my comment about the black hole thing in another of your recent posts.

A theory has evidence behind it in order to be "validated." You are using little or no experimental evidence to make your point. What you have right now are ideas. There is nothing wrong with this but if you want us to believe in your ideas you need evidence. Keep looking for it...I'm not saying there isn't any, but so far as I know GR has passed every test that has been made. (At least on the macroscopic size range. Gravity on the Quantum level doesn't have a testable theory yet.)

-Dan
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 Jan 16th 2018, 05:56 AM #12 Physics Team   Join Date: Apr 2009 Location: Boston's North Shore Posts: 1,533 Just because you toss an object up and it falls back down accelerating on the way in no way implies that gravity is not a conserved force. You don't appear to know the mean I g of that term. A force is said to be conserved if it can be expressed as the gradient of a scalar function or equivalent if the energy of an object in a field subject to that force remains constant, which is always true for any gravitational field which is constant in time. topsquark likes this.
 Jan 16th 2018, 08:11 AM #13 Physics Team   Join Date: Apr 2009 Location: Boston's North Shore Posts: 1,533 Just because you toss an object up and it falls back down accelerating on the way in no way implies that gravity is not a conserved force. You don't appear to know the mean I g of that term. A force is said to be conserved if it can be expressed as the gradient of a (time independent) scalar function or equivalently if the energy of an object subject a conservative force is constant in time, which is always true for any gravitational field which is constant in time. Dan - I think you may have confused the concepts of conserved and invariant. E.g. a particles 4-momentum is always invariant but isn't always conserved. Recall that invariant means to remain unchanged by a valid change in coordinates. Did I misinterpret your comment on this above? topsquark likes this.
Jan 16th 2018, 11:59 AM   #14

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 Originally Posted by Pmb Dan - I think you may have confused the concepts of conserved and invariant. E.g. a particles 4-momentum is always invariant but isn't always conserved. Recall that invariant means to remain unchanged by a valid change in coordinates. Did I misinterpret your comment on this above?
Nope. You read it right. Thanks for the catch.

-Dan
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Jan 16th 2018, 04:38 PM   #15
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 Originally Posted by topsquark Nope. You read it right. Thanks for the catch. -Dan
No problemo . Glad to be of service

 Tags conserved, fictitious, force

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