Timeline for Is Galilei's reasoning on free fall valid?
Current License: CC BY-SA 3.0
13 events
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| Jan 8, 2014 at 18:16 | comment | added | Valter Moretti | Well, I disagree: the statement is formally clear, the physical meaning is obscure, in my view ;). In the past I spent much time thinking about that statement, I think is time to give up, even because the webpage complains as you noticed. Bye, V. | |
| Jan 8, 2014 at 18:13 | comment | added | Ján Lalinský | I agree that the statement is not formally perfect, but I think its meaning is pretty clear. I'm sorry that you do not see it that way. Thanks for your view and time:-) Webpage complains about long series of comments, so for the time being, let's agree to disagree:-) | |
| Jan 8, 2014 at 18:00 | comment | added | Valter Moretti | The rules of the game are not defined and the reasoning relies upon a rhetorical argumentation only. | |
| Jan 8, 2014 at 17:57 | comment | added | Valter Moretti | Well this point in particular: "the original heavy body is being inhibited in its fall by the connected light body, since this "wants" to fall with less rapidity". It is a "non sequitur". What does "wants" mean there? It is not possible to achieve any conclusion like Galileo's one, in my opinion, without a precise notion of dynamics and interaction, for instance the Newtonian one (but not necessarily that). | |
| Jan 8, 2014 at 17:45 | comment | added | Ján Lalinský | Thanks, but so far I fail to see the problem. Do you think yours is the same as lionelbrits's objection? (I am not sure I understood him that well either.) | |
| Jan 8, 2014 at 17:16 | comment | added | Valter Moretti | "Could you say where exactly goes above reasoning wrong?" Here: " But on the other hand, the original heavy body is being inhibited in its fall by the connected light body, since this "wants" to fall with less rapidity. Due to this inhibition, the heavy body part should fall with less rapidity than it falls normally alone." | |
| Jan 8, 2014 at 17:03 | comment | added | Ján Lalinský | You may be right that a interpret Galileo differently than he meant, but I am more interested in whether the basic idea is right than in what Galileo originally meant. | |
| Jan 8, 2014 at 17:02 | comment | added | Ján Lalinský | I do not understand your last comment. Galileo almost certainly did not use concepts of inertial and gravitational mass, but that does not make his reasoning obviously incorrect. In general theory of relativity there is only one kind of mass, and this is not taken against it, on the contrary, its incorporation into theory is considered as a great accomplishment by Einstein. Could you say where exactly goes above reasoning wrong? | |
| Jan 8, 2014 at 16:38 | comment | added | Valter Moretti | Notice that we have two notion of mass to consider: The falling bodies behave as we know because inertial and gravitational mass are identical, this is not mentioned in Galileo's reasoning. I do not think the reasoning is correct. You are interpreting a posteriori Galileo's "proof", in my view. You should not read what it is not written therein. However I know many many opinions about that "proof"! Some colleagues of mine think that it is obviously right! | |
| Jan 8, 2014 at 16:26 | comment | added | Ján Lalinský | Good point, the argument is not valid for acceleration due to electrostatic field. But I do not think this invalidates Galileo's reasoning. It assumes that acceleration in free fall is a function of the mass only, which if we translate to electrostatic accelerations as "acceleration is a function of the charge only" is not satisfied. This may be the reason the rest of Galileo's argument does not lead to correct result. In this way, some character of gravitational interaction seems to be involved in the reasoning. | |
| Jan 8, 2014 at 15:38 | history | edited | Valter Moretti | CC BY-SA 3.0 |
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| Jan 8, 2014 at 15:26 | history | edited | Valter Moretti | CC BY-SA 3.0 |
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| Jan 8, 2014 at 15:20 | history | answered | Valter Moretti | CC BY-SA 3.0 |