Timeline for How come in free fall you feel weightless even though gravity is pulling down on you?
Current License: CC BY-SA 3.0
9 events
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| Feb 9, 2016 at 12:44 | comment | added | Nick | I explained some of these matters relating to weightlessness a few years back in this BBC article, which might help: news.bbc.co.uk/1/hi/magazine/4625150.stm | |
| Feb 9, 2016 at 12:26 | comment | added | Nick | p.s. I prefer 'reaction' force as it is more general. 'Normal' or 'normal reaction' implies one acting perpendicular to a surface, and it needn't be. | |
| Feb 9, 2016 at 12:22 | comment | added | Nick | I'm making a slightly subtle point: your body has no gravity sensors! - we can't directly detect weight, only external forces acting on our pressure sensing nerves. A set of weighing scales, for example, doesn't measure weight, it senses the third-law pair of the reaction force of the pan on the object. If you drop a weighing scale with an object in its pan, it records nothing - proof again that it does not measure weight, but reaction force. A falling person feels no reaction force - so 'feels' weightless - but we never feel our weight. I hope that is clearer. Kind regards | |
| Feb 8, 2016 at 12:52 | comment | added | Asher | @BruceLee I don't think Nick meant to say that it is impossible to feel any force while in free fall. Rather, he is pointing out the difference between the feeling of weight (which we only experience due to a reactive normal force) and of weightlessness (i.e. the absence of the usual normal force). If you and the chair are both in free fall you can still touch (apply force to) it, but it's not supporting you so you still "feel weightless." | |
| Feb 8, 2016 at 12:44 | comment | added | Bruce Lee | @Asher no one is disputing that...i am pointing out an apparent misunderstanding in the answer.. | |
| Feb 8, 2016 at 12:42 | comment | added | Asher | @BruceLee sit on a hard chair for a few hours and I guarantee you'll feel something. | |
| Feb 8, 2016 at 11:10 | comment | added | Bruce Lee | do you mean weightlessness means no normal forces? otherwise your argument is wrong as even sitting on a chair i feel no net external vertical force... | |
| Feb 8, 2016 at 10:52 | review | First posts | |||
| Feb 8, 2016 at 11:10 | |||||
| Feb 8, 2016 at 10:48 | history | answered | Nick | CC BY-SA 3.0 |