|Oct21-12, 12:06 PM||#1|
2 explanations for normal force
I have heard 2 informal explanations for the normal force during a situation like a book resting on a table:
1. The springiness of the atomic lattice in the table attempts to restore its original structure, thus pushing the book.
2. Since there are electrons on the outside of both the book and the table, the book is prevented from falling through (- repels -). Some even say this is the Pauli exclusion principle, not just electrostatic forces. Those particles cant occupy space already occupied.
Which one is correct, or are they both correct?
Then, if 2 is correct, say you wanted to float the book above the table using electrostatic forces. Would you need to put a charge on both the book and the table? Or could you just put a charge on the table and let induction push the book up (since all the electrons rush to the top of the book)? Thanks.
|Oct21-12, 12:50 PM||#2|
The springiness of the table is irrelevant. Even if it were a perfectly rigid object you would still get a repelling force between the atoms in the table and the atoms in the book thanks to their negatively charged electron clouds.
If you wanted to float the book a noticeable amount of distance above the table using electrostatics your would need to charge both the book and the table.
|Oct21-12, 09:47 PM||#3|
Ok, thanks. I had learned 2 as you said, but had seen 1 in some texts.
|Similar Threads for: 2 explanations for normal force|
|Frictional force, normal force and coefficient of friction||Introductory Physics Homework||3|
|Kinetic Friction, Undefined Pushing Force, Find Normal Force.||Introductory Physics Homework||4|
|Finding the Normal Force of a block on an incline experiencing centripetal force||Introductory Physics Homework||1|
|calculating normal force and net force of 20 kg mass going down inclined plane at...||Introductory Physics Homework||11|
|Free body diagram involving normal force, gravitational force, and applied force.||Introductory Physics Homework||4|