Any direct evidence of gravitational mass increase?

[PeroK]

Is this a claim that has anything to do with relativistic speeds, or are you just pointing out how vectors work?

It's the difference between classical three-vectors with three spatial components and relativistic four-vectors that also have a time component.

The equations of motion in relativity involve four-vectors and, indeed, we have:

##\textbf{f}## ## = m \textbf{a}##

For four-vectors.

 

[hkyriazi]

Something in your two posts gives me the impression that you are asking about gravitation in the context of Special Relativity, which does not deal with gravitation. If you are really asking about General Relativity, my apologies.

I tried to avoid GR by specifying that the rocket ship was non-accelerating. I'm trying to gain a fuller understanding of SR's relativistic mass increase.

 

[hkyriazi]

Well, in fact, there is a decreased gravitational effect. We could analyse the motion of a falling body using just SR and ignore GR:

[...]

Again, quite the opposite of what an advocate of relativistic mass might expect.

Thanks. A lot to grasp here. I'll print this out and chew on it a while, along with PAllen's response.

 

[hkyriazi]

There is two packed gas, say A and B, of the same amount. A is heated so average speed^2 of gas moecule is much higher than that of B. Say,
energy of A amount 1.1 kg c^2 > energy of B amount 1.0 kg c^2.
I reasonably assume that
energy of A as source of gravity 1.1 kg c^2 > energy of B as source of gravity 1.0 kg c^2
Honestly I do not know the experimental evidence achieved.

Good idea! This experiment gets at my question, and in a seemingly much more testable way.

 

[m4r35n357]

I tried to avoid GR by specifying that the rocket ship was non-accelerating.

Then you have this in reverse: GR is necessary for gravitation, it is not necessary for acceleration.

I'm trying to gain a fuller understanding of SR's relativistic mass increase.

There is no fuller understanding to be had, it is a dead end.