If there's a book resting a a table, (Newton's third law concept)

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SUMMARY

The discussion centers on the application of Newton's third law in the context of a book resting on a table. Participants clarify that the normal force acting on the book is exerted by the table, while the weight of the book acts downward due to gravity. It is established that these forces are not a third law force pair, as they act on the same body. Instead, the reaction force to the weight of the book is the force that the book exerts on the Earth.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Familiarity with the concepts of normal force and gravitational force
  • Basic knowledge of force pairs in physics
  • Ability to analyze forces acting on objects in different orientations
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  • Study the implications of inclined planes on normal force calculations
  • Explore examples of third law force pairs in various physical scenarios
  • Learn about the relationship between mass, weight, and gravitational force
  • Investigate the effects of friction on normal force in different contexts
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Students of physics, educators teaching mechanics, and anyone interested in understanding the principles of force interactions in classical mechanics.

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Homework Statement


would you say that "the two forces exerted on the book ar ethe normal force directed up and the weight of the book directed down. These are equal and opposite to one another. By Newton's third law they are a third law force pair, so the normal force is always equal to the weight of the book."


The Attempt at a Solution



I said disagree, since the normal force is exerted by the table, not the book, and the rest of the concept seems right.

right?

thanks
 
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You are correct to disagree. What if the table were inclined? Would the normal force on the book equal the weight mg?
 
Last edited:
"They are a third law force pair"
They're not...
both forces exerted on the same body, the reaction force of mg(aka weight) is the force the body exerts on Earth.
 

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