Basically I am trying to point out is that , you aren't sure if objects with more inertia fall a tad bit faster . You can't ever be sure .

Because newton's law itself is an experiment law.

One of the assumptions of special relativity is that a uniform gravitational field is identical to acceleration. It isn't a measurement of the real world but an exact assumption.

May be , because I didn't read the relativity part of the book , now your statement makes me feel mine is wrong . But I quoted what was written in the book.

I wouldn't be surprised if general relativity is only a very good approximation of things. Especially if gravity really is a quantum phenomena.

Can you then support your reasoning ? As to inertial mass which we defined according to accelerations through interactions turned out to be something cosmic . How did that happen ?

Its like I defined a metre and that metre turned out be something cosmic in whose terms the universe measured itself .

@BrandonEnright general relativity, actually

Or may be special relativity's assumption too is just an approximation ?

But yes, general relativity fully explains why gravitational mass and inertial mass are equal

Principle of Equivalence it is ? What you said @Brandon

@DavidZaslavsky They are fully equal ? Or approximately ?

Precisely equal

Precisely = Absolutely ?

take a look: kallikanzarid.blogspot.ru/2013/05/does-wind-affect-bullets.html

They are equal. Period. As in, in GR there is no distinction to be made between gravitational and inertial mass because they are the same thing.

i think i did it

@nonagon it's not a matter of measurement. It's not like measuring a meter where you can only get so many decimal places of precision. The concept of distance is a concept and the meter just happens to be a fixed unit of distance. A meter and a foot are two different measures but the thing they are measuring (distance) is EXACTLY the same thing.

I'm not sure about dimensions though, so I may have made a couple of errors

Alright , thank you .

@DavidZaslavsky you're right! I thought special relativity also handled cases of constant acceleration and uniform gravitational fields and general relativity handled non-uniform / changing acceleration and gravitational fields. It seems special relativity doesn't handle acceleration at all. It's been too many years since I did this stuff :-)

You can handle accelerated motion in SR, but not gravity. It always assumes flat spacetime.

And F=ma in general relativity ?

@nonagon No. GR only has F=ma in the limiting case of low velocities and low acceleration

Then what is inertial mass ?

Inertial mass got defined due to F=ma

mass in an inertial frame of reference, duh

If F!=ma , then how can m in newtonian terms equal the inertial mass in General Relativity ?

by m I mean inertia in newtonian mechanics

ok , thanks .

Geodesic Equation ?

might be useful

General relativity is so much more complicated than special. It was impressive enough that Einstein developed SR. Turning that into GR is incredible.

@Gugg Amusingly, most of the friction he had with Philosophy appears to be due to his refusal to correctly spell Nietzsche. I can't imagine he would have intentionally misspelled t' Hooft, though.

@ColinMcFaul Ron's profiles are always so entertaining. From his Philosophy profile "I believe the field is bankrupt intellectual fraud, with a handful of honest practitioners who didn't achieve any progress, because they are drowned out by impressive sounding political clowns."

@ColinMcFaul You misspelled it as well :P Not sure if it was intentional

@ChrisWhite I'm not familiar enough with the field. Most of the philosophy I've read is philosophy of the mind and especially the Penrose idea of quantum wavefunction collapse being the underlying mechanism neurons use.

My point is primarily that if you want to be respected at all you probably shouldn't hurl generic insults at an entire field.

I find a lot of philosophy pointless

There's interesting stuff there, but a lot of it is pointless

Hmm this Kant guy sounds interesting. I especially agree with the quote from Wikipedia "Kant believed the concepts of space and time were programmed into the human brain, as was the notion of cause and effect. We never have direct experience of things"

@ChrisWhite well, in the end, ALL science is philosophy in a way :P

I'm not sure how appropriate it is to discuss here however after experimenting with some powerful dissociative drugs I have a much greater appreciation for how much of our perception of the world is based on our brain trying to maintain the illusion consistency.

@ChrisWhite this is basically the first I've heard of him.

@ChrisWhite Exactly