What Happens if Newton's Third Law is Violated?

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Discussion Overview

The discussion explores hypothetical scenarios regarding the implications of violating Newton's Third Law, particularly focusing on situations where action and reaction forces are not equal in magnitude or size. Participants consider the theoretical consequences of such violations on fundamental principles like momentum conservation and the nature of forces in contact and at a distance.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that if action and reaction forces are unequal, momentum would not be conserved, leading to a breakdown of physical invariance under spatial translations.
  • There is a discussion about the nature of contact forces, with some arguing that equal and opposite forces are necessary for two objects to remain in contact, while others suggest that the Third Law applies regardless of contact.
  • One participant questions the implications of unequal forces in various physical activities, such as running or jumping, raising the idea of how these scenarios would challenge Newton's laws.
  • A participant introduces a speculative scenario about an object's inertia dropping to zero, questioning the foundational reasons behind Newton's laws rather than their descriptive nature.

Areas of Agreement / Disagreement

Participants express differing views on the implications of violating Newton's Third Law, with no consensus on the nature of contact forces or the consequences of unequal forces in various scenarios. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Some claims depend on interpretations of contact and force definitions, and there are unresolved assumptions regarding the nature of forces in hypothetical scenarios.

Mt. Nixion
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What would happen if (if ever) when the action force is greater than or less than the reaction force and were not equal in magnitude and were not equal in size?
 
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Mt. Nixion said:
What would happen if (if ever) when the action force is greater than or less than the reaction force and were not equal in magnitude and were not equal in size?

Momentum would not be conserved ; which would translate into physics not being invariant under translations in space.
 
Well, that depends on your understanding of what is contact. Two objects in contact due to force exert equal and opposite force to each other so that they remain in contact. The third law is just a continuation of this concept and is not an independent law. But it is simply surprising that this also applies on two remote objects which are not in contact if the considered force is gravitational or electrostatic of distant objects.
 
vaishakh said:
Two objects in contact due to force exert equal and opposite force to each other so that they remain in contact.
What do you mean? Are you implying that as long as the 3rd law is satisfied, two objects must remain in contact?
 
I mean that is esential for two objects to remain in contact. Correct if I am wrong
 
Two objects that come into contact will exert equal and opposite contact forces on each other in accordance with Newton's 3rd law. It doesn't matter whether they remain in contact with each other or separate; Newton's 3rd law is satisfied either way.
 
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Mt. Nixion said:
What would happen if (if ever) when the action force is greater than or less than the reaction force and were not equal in magnitude and were not equal in size?

force either comes in magnitude or in size , not both.
 
Another question; what if the forces in Newton's third law were not equal for things like running, throwing, jumping, lifting, kicking, punching, squeezing, stretching and breaking?
 
Netwon's Laws merely describe how we see the world work. They do not have anything to do with why they work like that.

I suspect what you want to propose is something like: what if an object's inertia managed to drop to zero? What would happen?
 

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