Does an Apple’s Gravity Influence Earth’s Movement?

  • Context: Undergrad 
  • Thread starter Thread starter mtasquared
  • Start date Start date
  • Tags Tags
    apple Falling Ground
Click For Summary

Discussion Overview

The discussion revolves around the gravitational interaction between an apple and the Earth when the apple falls. Participants explore the implications of this interaction on the movement of the Earth and question the common assumption that the Earth remains stationary in physics problems. The scope includes conceptual reasoning and technical clarification regarding gravitational effects.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that an apple exerts its own gravitational pull on the Earth, potentially affecting the distance it falls.
  • Others argue that the Earth's acceleration due to the apple's gravitational pull is negligible and thus often ignored in physics problems.
  • A participant suggests that while simplifying calculations is beneficial for students, it is important to acknowledge that the apple does cause a very small acceleration of the Earth.

Areas of Agreement / Disagreement

Participants express differing views on the significance of the apple's gravitational influence on the Earth, with no consensus reached regarding the treatment of this interaction in physics problems.

Contextual Notes

Limitations include the assumption that the gravitational effect of the apple is negligible, which may depend on the context of the problem and the definitions used in calculations.

mtasquared
Messages
10
Reaction score
0
When an apple falls to the ground does it not exert some gravity of it's own on the Earth and thus shortening the distance it falls? Why is it always assumed the Earth does not itself move in physics problems?
 
Physics news on Phys.org
mtasquared said:
When an apple falls to the ground does it not exert some gravity of it's own on the Earth and thus shortening the distance it falls?
Sure.
Why is it always assumed the Earth does not itself move in physics problems?
Estimate the Earth's acceleration due to the apple's gravitational pull. Then you'll see why it's ignored.
 
mtasquared said:
When an apple falls to the ground does it not exert some gravity of it's own on the Earth and thus shortening the distance it falls? Why is it always assumed the Earth does not itself move in physics problems?

The idea of ignoring negligible calculations is to make it easier for students who are introduced to these concepts to make the calculations. However I think it should still be said to the students that the apple is causing the Earth to undergo a very very very small acceleration, so that they can be reminded that forces affect both objects.
 
Thanks for replying!
 

Similar threads

Undergrad An apple falls from a tree, Does the moon move as a result?
  • · Replies 2 ·
Replies
2
Views
2K
High School Why Is It That An Apple Will Fall To The Earth?
  • · Replies 9 ·
Replies
9
Views
3K
High School Does the inverse square law equalize gravity at different spots?
  • · Replies 8 ·
Replies
8
Views
2K
Graduate Falling apple inside a space centrifuge
  • · Replies 11 ·
Replies
11
Views
2K
High School Why Does an Apple Fall to Earth, But Earth Doesn't Fall to the Apple?
  • · Replies 9 ·
Replies
9
Views
20K
Undergrad Normal force and details of the Earth holding up an object
  • · Replies 12 ·
Replies
12
Views
2K
Undergrad How to Calculate force exerted on a falling body?
  • · Replies 12 ·
Replies
12
Views
3K
Graduate Please Explain Elementary Physics Elevator Question
  • · Replies 22 ·
Replies
22
Views
2K
Undergrad Source of Gravity of heavy mass as per GTR
  • · Replies 14 ·
Replies
14
Views
2K
Undergrad Why don't we consider Earth's forces/movement in problems?
  • · Replies 22 ·
Replies
22
Views
2K