# Normal force between objects [duplicate]

If a book is kept on a table , will the book also apply a normal force on the table ? Then which of the two normal forces( one by book and other by table) would be considered as action force and reaction force ? Thank you in advance.

• I think you can say that either is true, it is just a matter of definition. Usually we say that the force applied by the book on the table is the action and the table responds with the reaction. – Filipe Miguel Mar 30 '19 at 11:16
• Ok , so does the book applies a normal force on the table . – Ashok Sharma Mar 30 '19 at 11:17
• Yes, otherwise where would the reaction from the table come from? – Filipe Miguel Mar 30 '19 at 11:20
• How many times would this question be asked on this website? – user213933 Mar 30 '19 at 12:31

## 1 Answer

The book won't apply a normal force on the table, just a gravitational one. The reaction force of the gravitational force of the book is the normal force acting on the book.

• I am of the opinion that the book does not apply a gravitational force. The gravitational force is applied by the earth on the book. Is this wrong ? – Ashok Sharma Mar 30 '19 at 11:09
• Implicit in Newton's Third Law is that the nature of the so-called action and reaction forces are of the same type... both normal or both gravitational. If there is a relation involving a normal force and gravitational force, Newton's Second Law must be involved. – robphy Mar 30 '19 at 11:20
• This answer is wrong – Aaron Stevens Mar 30 '19 at 12:08
• This answer is completely out of scope of mine!!! – user213933 Mar 30 '19 at 12:35