# Contact force and bending

1. Sep 22, 2015

### tonyjk

Hello,

When we have 2 bodies in contact with each other, for example a book lying on the surface of a table. The table's molecules bend a little bit because of the weight of the book thus producing the contact force. My question is this contact force acting on the book does also bend the molecules of the book?

Thanks.

2. Sep 22, 2015

### Staff: Mentor

Yes.

3. Sep 22, 2015

### nasu

Only of you consider the "bending" of molecules as a metaphoric expression.

4. Sep 23, 2015

### tonyjk

Hello Again,
During collision is there any compression of both objects? if yes, the collision is considered as elastic or non elastic ?

Thank you

Last edited: Sep 23, 2015
5. Sep 23, 2015

### nasu

Yes, there is compression (deformation) for both elastic and plastic collisions.

6. Sep 24, 2015

### tonyjk

Is the impulse force makes the deformation of the surface and the reaction force makes it on the second surface?

7. Sep 24, 2015

### A.T.

That's an irrelevant disctinction. Both forces in Newtons 3rd Law are on the same footing, and the choice which surface ist 1st and which 2nd is arbitary.

8. Sep 24, 2015

### tonyjk

But do these forces make the deformation?

9. Sep 24, 2015

### A.T.

The forces are quantitatively related to the amount of deformation.

10. Sep 24, 2015

### tonyjk

Ok but the forces do not deform the surfaces?

11. Sep 24, 2015

### A.T.

If there is deformation, then there are forces. And vice versa. Physics tells you how they are related quantitatively. The rest is philosophy.