Just because we measure it to be the same does not mean that the two are directly related. Inertial mass and gravitational mass are apples and oranges at this point because no one has any idea of how to derive one from the other to show they are the same. This is a very deep question in the Philosophy of Physics and anyone that can show they are the same from a theoretical viewpoint would probably get a Nobel Prize.Only virtually the same ??? What experiments show a difference??? In Physics experiment is everything ...I don't see what debate there can be unless there is experimental evidence of a discrepancy .

To a degree the difference in viewpoints does not affect the theory. It's just that it is somewhat easier to work with momentum because it is easier to write out the QM equations. Note that \(\displaystyle E = mc^2\) is only true for an object at rest. The actual equation is \(\displaystyle E^2 = (mc^2)^2 + (pc)^2\). The momentum term is already in there so it's more natural to use.Really ?? I didn't know that !! Are you saying mass doesn't increase with speed???

I was taught that the kilo of sugar in my kitchen reacted to other mass by the well known gravity equation , and accelerated from force by F=Ma ..

And this kilo mass increased by the well known formulae as it's speed increased , becoming infinite at the speed of light .

As far as I know all this still stands.

The reason my kilo of sugar can be more than a kilo is because I've increased its energy and energy is equivalent to mass ...E=mc2

-Dan

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