How do action reaction force pairs arise?

  1. Hi guys,

    What is the reason for action-reaction force pairs to arise?
    Is it a consequence of electrostatic repulsion due to interaction of the 2 bodies, or can it be explained using energy conservation or momentum conservation.

    Thanks!
     
  2. jcsd
  3. rcgldr

    rcgldr 7,542
    Homework Helper

    It's an axiom or postulate that is just assumed to be self-evident and true. I'm not sure there's a way to prove it. Almost all forces invoved some type of reaction if you look at a situation from a large enough scale, and consider things like how much the earth is affected by a car acclerating on it's surface.

    In some cases, a Newton 3rd law pair doesn't require physical contact, such as gravity, where the third law pair is the equal and opposing attractive force on each body in a two body system.
     
  4. You could derive force pairs from momentum conservation of arbitrary pairs of objects, but we tend to think of actio = reactio as being more fundamental.
     
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