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Weightlessness on Earth's Surface

  1. Sep 17, 2006 #1
    Suppose that I am standing on the surface of the Earth. Then the only forces acting on me is the force of gravity that is pulling me down and the normal force exerted by the ground that is pushing me up. These forces are equal and opposite in direction and thus there is no net force acting on me. Then why is it that I don't feel weightless?
  2. jcsd
  3. Sep 17, 2006 #2
    In order to feel weightless you would need to have no normal force.
  4. Sep 17, 2006 #3


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    It's exactly the opposite. The sensation of weight is given by the normal force acting on you. In free fall the only force acting on you is gravity, so you fell weightless.
  5. Sep 17, 2006 #4
    I win.

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  6. Sep 17, 2006 #5
    Really? So if you have no net force acting on yourself, then wouldn't you feel weightless? For example, say you are traveling in a spaceship with a constant velocity in free space with no gravitational force, then aren't you weightless?
  7. Sep 17, 2006 #6
    No, you would feel your weight becuase there is a normal force.

    In the case of the spaceship, there is zero force, not zero net force.

    If you were in freefall, your net force would be F=mg, and you would have an apparent weightlessness, because there is no normal force once again.
    Last edited: Sep 17, 2006
  8. Sep 17, 2006 #7


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    Staff: Mentor

    Didn't we have this exact question asked in another way in another thread?

    No net force does not mean no force, it just means no net force. It seems pretty obvious to me...
  9. Sep 17, 2006 #8
    Everything is obvious when you know the answer. :wink:
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