Difference between gravitational and inertial mass

[MikeGomez]

No, it doesn't.

D H, the implication that the equivalence of gravitational mass with inertial mass leads to equivalence of gravitation with inertia seems reasonable, and this probably comes up fairly often. It’s an interesting idea. When you say “no, it doesn’t”, do you mean that the equivalence principle doesn’t go as far as to say that, or do you mean that in a stronger sense, such that you have an argument which specifically contradicts this idea.

 

[DrStupid]

He said “Bodies which are moving under the sole influence of a gravitational field receive an acceleration, which does not in the least depend either on the material or on the physical state of the body. For instance, a piece of lead and a piece of wood fall in exactly the same manner in a gravitational field (in vacuo), when the start off from rest or with the same initial velocity.”

In this wording - especially with the limitation to the same initial velocity - it is correct. The weak equivalence principle without this limitation is not correct.

I do not see any indication that they are trying to advance the idea that gravitational mass is different from inertial mass.

If they assume gravitational and inertial mass to be equal, how do they come to their conclusion "In the ultrarelativistic limit, the $\left( {1 + \beta ^2 } \right)$ factor approaches the value 2 and is than the same famous factor by which the general relativistic prediction for light bending excess the Newtonian prediction."? This factor is nothing else than the ratio between gravitational and inertial mass as used in Newtonian mechanics and in the case of light it has already been proofed experimentally.

If you do the math properly, or if you could actually run the experiment in an equivalent manner, you would find the same results of “increased gravitational attraction” in the relativisticly accelerated frame.

Different accelerations at the same position will not become equal by changing the frame of reference.

 

[MikeGomez]

If they assume gravitational and inertial mass to be equal, how do they come to their conclusion "In the ultrarelativistic limit, the $\left( {1 + \beta ^2 } \right)$ factor approaches the value 2 and is than the same famous factor by which the general relativistic prediction for light bending excess the Newtonian prediction."? This factor is nothing else than the ratio between gravitational and inertial mass as used in Newtonian mechanics and in the case of light it has already been proofed experimentally.

Apologies. I suppose that Olson-Guarino do propose the idea that gravitational mass is different from inertial mass. If you believe this also, and others on this forum do as well, then I suppose that I may be in the minority on that.

 

[D H]

That is an extremely suspect journal article. It has been in publication for almost thirty years and has been cited *twice* in that time, once in a Physics Essays article (we do not allow that journal at this site), and the other time in a Beyond the Quantum workshop paper (we generally don't allow those, either).