Why Is the Electromagnetic Force of the Table on the Book Considered Negligible?

  • Thread starter Thread starter briton
  • Start date Start date
  • Tags Tags
    Table
Click For Summary

Homework Help Overview

The discussion revolves around the electromagnetic forces at play between a book resting on a table and the forces exerted by both objects. Participants are exploring the nature of these forces, particularly questioning why the electromagnetic force of the table on the book is considered negligible in comparison to gravitational forces.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the action/reaction force pairs involving gravitational and electromagnetic forces, questioning the significance of the electromagnetic forces. There is an exploration of the ionic and molecular interactions that contribute to the forces between the book and the table.

Discussion Status

The discussion is active, with participants raising questions about the nature of electromagnetic forces and their implications. Some have provided insights into the forces involved, while others are seeking deeper understanding of the molecular interactions at play.

Contextual Notes

Participants are navigating assumptions about the forces involved and the scale at which they operate, particularly in relation to gravitational forces. There is an acknowledgment of the complexity of the interactions at the molecular level.

briton
Messages
30
Reaction score
0
A book on a table.
the gravitational force of attraction of the bookon the Earth is negligible...

if the reaction force is the electromagnetic force of repulsion of the book on the table, then why is the electromagnetic force of the table on the book negligible??
 
Physics news on Phys.org
briton said:
A book on a table.
the gravitational force of attraction of the bookon the Earth is negligible...
The action/reaction force pair is this: The Earth exerts a gravitational force on the book, and the book exerts and equal (but opposite) gravitational force on the earth. (Of course, the effect of that force on the massive Earth is negligible.)


if the reaction force is the electromagnetic force of repulsion of the book on the table, then why is the electromagnetic force of the table on the book negligible??
Now you are talking about a different set of forces: The book pushes on the table (electromagnetic forces involved) and thus the table pushes on the book with an equal force. The force on the book is not negligible--after all, it's what's holding the book up!
 
Doc Al said:
The action/reaction force pair is this: The Earth exerts a gravitational force on the book, and the book exerts and equal (but opposite) gravitational force on the earth. (Of course, the effect of that force on the massive Earth is negligible.)



Now you are talking about a different set of forces: The book pushes on the table (electromagnetic forces involved) and thus the table pushes on the book with an equal force. The force on the book is not negligible--after all, it's what's holding the book up!
sorry, I meant the electromagnetic force of the book on the table - this isn't negligible is it? It is of the same magnitude, but in an opposite direction to the force of the table on the book. mm I guess wht I really want to know, is what's happening on the ionic/molecular level... how is the table pushing with an electromagnetic/static force and how is the book pushing back?
 
Isn't it that the electrons of the book's molecules are close enough to the electrons of the table's molecules to provide sufficient repulsive force to keep the book afloat? (They're not really touching!)
 

Similar threads

  • · Replies 8 ·
Replies
8
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
15K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 29 ·
Replies
29
Views
4K
Replies
4
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K