The difference b/t free fall and outer space

In summary, the apple will move closer to you if the elevator is in free fall, and it will be standing still if you're in the outer space.
  • #1
HungryChemist
143
0
You are in the closed elevator with the apple. You feel weightless. So you want to know whether you're free falling or in the outer space. Place the apple about a meter away from your eyes. If the elevator is in free fall, the apple will move close to you slowly, but if you're in the outer space the apple will be standing still. Because in free fall elevator, the gravitational force acting on the apple, in small scale, is not parallel to the gravitational force acting on you.
 
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  • #2
Or indeed if you place it 'above' you you wil start to move away from it or simlairly you might notice you start be strecthched a little by tidal forces. This is because usually (infact in all but the most ridculous of situations) graviational fields are not homogenous (though perhap by assuming sherically symmetric graviational fields you (and I) shouldn't make conclusions about gravitational fields in general)

Howvere this is not a problem for the equivalence priniple, as the equivalence principle only really refers to highly localized frames of reference, so the elevator has vanishingly small volume, infact it really is just a geometric point.
 
  • #3
jcsd said:
Or indeed if you place it 'above' you you wil start to move away from it or simlairly you might notice you start be strecthched a little by tidal forces. This is because usually (infact in all but the most ridculous of situations) graviational fields are not homogenous (though perhap by assuming sherically symmetric graviational fields you (and I) shouldn't make conclusions about gravitational fields in general)

Howvere this is not a problem for the equivalence priniple, as the equivalence principle only really refers to highly localized frames of reference, so the elevator has vanishingly small volume, infact it really is just a geometric point.


I got it!
 

Related to The difference b/t free fall and outer space

What is free fall?

Free fall is the motion of an object under the sole influence of gravity. This means that the object is falling towards the ground with no other forces acting upon it.

What is outer space?

Outer space is the vast, empty expanse beyond the Earth's atmosphere. It is a vacuum, meaning it contains no air or other matter, and is mostly composed of empty space.

What is the main difference between free fall and outer space?

The main difference between free fall and outer space is that free fall occurs within a gravitational field, while outer space is the absence of a gravitational field. In other words, free fall is a result of gravity pulling an object towards the Earth, while outer space is a lack of gravity altogether.

Can an object be in free fall while in outer space?

Technically, yes. If an object is falling towards the Earth while in outer space, it is still considered to be in free fall. However, once the object reaches the Earth's atmosphere, air resistance will cause it to no longer be in free fall.

What other factors differentiate free fall and outer space?

In free fall, an object is constantly accelerating towards the ground due to the force of gravity. In outer space, an object may continue to move at a constant speed or change direction due to other forces, such as propulsion systems or gravitational pulls from other celestial bodies.

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