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# Reaction force of an object watch

1. Considering a book resting in equilibrium on a table, what exact interaction is occurring at an inter-atomic level for the electrostatic reaction force from the table onto the book for the table to hold the book up(considering both objects are neutrally charged)? (hence similarly, how is the book exerting its own electrostatic force onto the table)

I think it’s something to do with potential energy increasing (becomes more positive) as atoms approach each other (something like the graph below?) which then produces an electrostatic/magnetic repulsion, but no idea howaccurate this is.. can anyone clear this up please?
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2. (Original post by endeavour)
Considering a book resting in equilibrium on a table, what exact interaction is occurring at an inter-atomic level for the electrostatic reaction force from the table onto the book for the table to hold the book up(considering both objects are neutrally charged)? (hence similarly, how is the book exerting its own electrostatic force onto the table)
This bit i think i can understand: the electrons are on the outside of the atom/molecule so when you start bringing them together, there is a repulsion between the two layers of electrons. This is the electrostatic repulsion - it doesn't really matter that the overall charge on the atom is zero, because the nucleus (positive bit) doesn't take part. The repulsion increases exponentially as you bring the things together (because it's an inverse square law), so at some point the force pushing them apart becomes equal to the force pushing them together (weight of book).

I couldn't comment on Hooke's law - I can't remember it in enough detail - dammit, there's something else to revise.

Is this what you were asking?
3. Hmm - that diagram below the graph shows (i think) that the two atoms are in equilibrium with just a little overlap (but not close enough to bond). Perhaps this is because since the two atoms have to be pretty damn close there's a little distortion in the shape of the electron orbitals (ie. not spherical) because of the repulsion going on...is this right anyone?
4. (Original post by endeavour)
Considering a book resting in equilibrium on a table, what exact interaction is occurring at an inter-atomic level for the electrostatic reaction force from the table onto the book for the table to hold the book up(considering both objects are neutrally charged)? (hence similarly, how is the book exerting its own electrostatic force onto the table)

I think it’s something to do with potential energy increasing (becomes more positive) as atoms approach each other (something like the graph below?) which then produces an electrostatic/magnetic repulsion, but no idea howaccurate this is.. can anyone clear this up please?
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Right not too sure myself. But Pretty confident as you say it is atomic forces. Definitely electrostatic. So the charges are repulsive. for like charges (ie the electrons) so the atoms push each other apart. Thats really all there is too it that I can see. I mean the harder you push the closer you push the atoms and so the stronger the reaction force - hence they always balance.

That should be about all you need.

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