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Suppose you are in an elevator and you and the elevator free-fall under the influence of gravity, you feel weightlessness. This weightlessness is because the Normal Force due to the elevator is $0$ N.

Now, suppose it's you without the elevator. The force due the air molecules [Normal Force] is $0$ N, if the fall is truly free-fall. But, in a general fall of an object when you drop it from the top of a building:

  • Will you feel weightless?
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  • $\begingroup$ There will obviously be some wind resistance pushing against you. You could use that to argue that you aren't in "freefall", because you will reach some terminal velocity. I'm not really sure what the intent of the question is though. $\endgroup$ – JMac May 1 '17 at 12:00
  • $\begingroup$ Just wanted to confirm that. $\endgroup$ – PhyEnthusiast May 1 '17 at 12:00
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    $\begingroup$ But "feel weightless" is somewhat vague. You would probably "feel" weightless, especially at first when velocity is low and therefore drag is very low. As you accelerate this feeling will go away slightly. $\endgroup$ – JMac May 1 '17 at 12:05
  • $\begingroup$ @JMac Do you mean "as you decelerate the feeling will go away"? ie as you reach terminal velocity. You have the maximum acceleration (g) when your velocity is zero. Your 1st comment was better : at terminal velocity you will feel "heavy" again, as when touching the ground. $\endgroup$ – sammy gerbil May 2 '17 at 18:56
  • $\begingroup$ @sammygerbil I was taught to avoid terms like "decelerate", but yes I meant acceleration was decreasing. $\endgroup$ – JMac May 2 '17 at 19:00
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Atmospheric drag will decelerate you, so you won't feel weightless.

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    $\begingroup$ Furthermore, falling at terminal velocity will feel almost exactly like lying on the floor, since it is a 1G normal force in both cases - ignoring the fact that one floor is much windier than the other. $\endgroup$ – Asher May 1 '17 at 15:41
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You would feel weightless as long as you were accelerating at 1G. As others have stated wind resistance will decrease your acceleration until friction is equal to 1G.

This results in an odd phenomenon with falling cats. It was noticed that cats that fell from around 4 floors were seriously injured or died but there have been many documented cases of cats falling from much higher and being uninjured or only slightly hurt. Scientists studied this and discovered that up to around the 4th floor a falling cat is still accelerating and will tense up for the eventual impact but cats falling from above that approach terminal velocity and the cat no longer feels like it is falling. Being a cat it probably thinks it is the ruler of the universe and can now fly so it relaxes before impact with the ground resulting in less sever injuries.

http://www.bbc.com/news/magazine-17492802

Free fall is often used to describe the feeling

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  • $\begingroup$ Good cat anecdote. Didn't get where you were going with that until you brought up the tensing. Really gives a good example of "feeling" freefall. $\endgroup$ – JMac May 1 '17 at 14:10
  • $\begingroup$ Thanks, I was really intrigued when I listened to the talk on falling cats. The article I linked is not the same I heard but covers similar material. $\endgroup$ – Gwydionforge May 1 '17 at 14:50
  • $\begingroup$ The linked article does not actually say that cats have a greater chance of survival if they reach terminal velocity. $\endgroup$ – sammy gerbil May 2 '17 at 18:48
  • $\begingroup$ @sammygerbil No, it does not. But the story I listened to does. If you need me to, I can search for it and post a link. $\endgroup$ – Gwydionforge May 3 '17 at 0:11
  • $\begingroup$ For those fact checking down voters: en.wikipedia.org/wiki/High-rise_syndrome and this is the one I listened to radiosurvivor.com/2012/03/23/… $\endgroup$ – Gwydionforge May 3 '17 at 15:56

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