Gravity ```Name: Mmchan Status: N/A Age: N/A Location: N/A Country: N/A Date: 1991 ``` Question: Is there a place on Earth that a person can experience weightlessness? Replies: During swimming and during some amusement park rides a person may experience weightlessness. NASA also has a special plane used to train astronauts that performs a parabolic free-fall that produces weightlessness for about 90 seconds. It is affectionately known as the barf wagon. John Hawley Sure. Every time you jump from some height, during the fall you are experiencing the same "weightlessness" that the astronauts aboard the Shuttle experience. The term "weightlessness" is rather deceiving; to some people it implies that it is a condition in which gravity is not acting (a "zero-G" environment). Not so. It is more correct to say that the astronauts are in free fall; they, their craft, and its contents are all continuously falling, under the action of the Earth's gravity. Since they all fall at the same rate, the falling cannot be perceived by the astronauts; the only motion they see (if they do not look out at the Earth) is their relative motion to one another, the interior of the ship, etc. When the first astronauts were being trained, one thing that was done was to take them up several thousand feet in a plane, then the plane would go into a dive in which it was essentially free-falling. This was intended to duplicate to some extent, for a few seconds, the free-fall environment they would experience while in orbit. It is proper to think of an orbit as a continuous fall; this is in fact how Isaac Newton came to view the orbit of the Moon around the Earth, and that realization helped him to perceive that the fall of objects (like apples) near the Earth's surface and the orbiting of the Moon are two instances of the same physical phenomenon -- gravitation. But if you are asking if there is a place on earth where you can exper- ience this free-fall condition without actually falling, I would say no. rcwinther Click here to return to the Physics Archives

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