The difference b/t free fall and outer space

Click For Summary
SUMMARY

The discussion clarifies the distinction between free fall and outer space using a closed elevator scenario. When in free fall, an object like an apple will appear to move towards the observer due to the non-parallel gravitational forces acting on both. In contrast, in outer space, the apple remains stationary relative to the observer. The equivalence principle is highlighted as it pertains to localized frames of reference, emphasizing that gravitational fields are typically not homogeneous.

PREREQUISITES
  • Understanding of gravitational forces
  • Familiarity with the equivalence principle
  • Basic knowledge of tidal forces
  • Concept of localized frames of reference
NEXT STEPS
  • Research the implications of the equivalence principle in general relativity
  • Study gravitational field variations and their effects
  • Explore the concept of tidal forces in astrophysics
  • Investigate the characteristics of localized frames of reference in physics
USEFUL FOR

Physics students, educators, and anyone interested in understanding the principles of gravity and motion in different environments.

HungryChemist
Messages
140
Reaction score
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.
 
Physics news on Phys.org
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.
 
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!
 

Similar threads

  • · Replies 51 ·
2
Replies
51
Views
5K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 21 ·
Replies
21
Views
3K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 51 ·
2
Replies
51
Views
6K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 7 ·
Replies
7
Views
3K