- #1
Mr-R
- 123
- 23
Dear all,
I am self studying GR and stuck on problem (23) on page 108/109. I am trying to do all of them.
First I will start with (a) so you guys can breath while laughing at my attempts at (b) and (c)
(a) Attempt
The tensor in the equation is bounded in the [itex]d^{3}x[/itex] region. Outside the region [itex]T^{\alpha\beta}=0[/itex]
[itex]\partial_t ∫T^{t\alpha}d^{3}x=0[/itex]. I will replace the derivative of the tensor with a spatial Div
[itex]=-∫T^{\beta\alpha}_{,\beta}d^{3}x[/itex]. Then using Gauss' law d^3x -> d^2x;
[itex]=-∫T^{\beta\alpha}d^{2}x[/itex]. It is not bounded by a region now but a surface which extends to infinity (??). So, unbounded? Therefore [itex]T^{\beta \alpha}=0[/itex]
I will continue to (b) and (c) after you guys set me up with (a).
Thanks in advance!
I am self studying GR and stuck on problem (23) on page 108/109. I am trying to do all of them.
First I will start with (a) so you guys can breath while laughing at my attempts at (b) and (c)
(a) Attempt
The tensor in the equation is bounded in the [itex]d^{3}x[/itex] region. Outside the region [itex]T^{\alpha\beta}=0[/itex]
[itex]\partial_t ∫T^{t\alpha}d^{3}x=0[/itex]. I will replace the derivative of the tensor with a spatial Div
[itex]=-∫T^{\beta\alpha}_{,\beta}d^{3}x[/itex]. Then using Gauss' law d^3x -> d^2x;
[itex]=-∫T^{\beta\alpha}d^{2}x[/itex]. It is not bounded by a region now but a surface which extends to infinity (??). So, unbounded? Therefore [itex]T^{\beta \alpha}=0[/itex]
I will continue to (b) and (c) after you guys set me up with (a).
Thanks in advance!
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