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amjad-sh

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- Thread starter amjad-sh
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In summary: This is what Newton did. He observed that momentum is conserved in collisions, and thus postulated that the law was true. Although technically correct, there are infinite postulates possible from where to choose. Generally speaking, one postulate things after some observations and experiments. This is what Newton did. He observed that momentum is conserved in collisions, and thus postulated that the law was true.

- #1

amjad-sh

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- #2

axmls

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It's a fairly intuitive one at that. Certainly if I punch a wall, I might do some damage to the wall, but the wall also does damage to me.

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Noctisdark

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By observation, like all physical laws, you can try out this expirement by yourself, try you push the wall, you'll notice that it's pushing you too. How do you jump ? You simply apply some force on the ground downward and it pushes you upward ! By repeating the same expirement, one can suggest that for any given force there is some reaction.amjad-sh said:

Good luck, hope I've helped !

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amjad-sh

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OK.

THANKS YOU BOTH HELPED!

THANKS YOU BOTH HELPED!

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DrStupid

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amjad-sh said:How did Newton predict his third law?

I think he started from conservation of momentum and the third law is a simple method to keep momentum constant. Of course the next question is: How did Newton predict conservation of momentum? Here I agree with Noctisdark that it results from experimental observations. As nobody ever observed that something changes its momentum without external interactions it is obvious to use this as an universal principle.

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brainpushups

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DrStupid said:I think he started from conservation of momentum and the third law is a simple method to keep momentum constant. Of course the next question is: How did Newton predict conservation of momentum? Here I agree with Noctisdark that it results from experimental observations. As nobody ever observed that something changes its momentum without external interactions it is obvious to use this as an universal principle.

Indeed, I believe this is correct. Newton respected, and was aware of, both Descartes and Huygens work. Both gentlemen (Descartes incorrectly, and Huygens correctly) formulated versions of the principle of conservation of momentum for collisions. It is not a stretch to cast this in terms of 'action' and 'reaction.'

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andresB

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Although technically correct, there are infinite postulates possible from where to choose. Generally speaking, one postulate things after some observations and experiments.axmls said:Newton's third law is simply a postulate. It must simply be accepted, and then the conclusions drawn from it are put to the test. If the test confirms the postulate, then you've got a good postulate.

Newton's third law states that for every action, there is an equal and opposite reaction. This means that when one object exerts a force on another object, the second object will exert a force back in the opposite direction. This allows us to predict the motion of objects by understanding how forces interact with each other.

Yes, Newton's third law can be applied to everyday situations. For example, when a person jumps off of a diving board, their feet exert a force on the board which causes the board to push back with an equal and opposite force, propelling the person into the air.

Yes, Newton's third law is always true. It is a fundamental law of physics that has been proven through countless experiments and observations. It applies to all types of forces and interactions, including gravitational, electromagnetic, and nuclear forces.

Newton's third law is directly related to the conservation of momentum. In a closed system, where there are no external forces acting, the total momentum remains constant. This is because for every action, there is an equal and opposite reaction, so the total momentum of the system is balanced.

Yes, Newton's third law can be used to predict collisions. When two objects collide, the forces they exert on each other are equal and opposite according to Newton's third law. By understanding these forces, we can predict the motion and outcome of the collision.

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