How does a force create a moment around a point without direct contact?

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Discussion Overview

The discussion centers on the concept of how a force can create a moment around a point without direct contact, exploring the theoretical implications and interpretations of moments in physics. The scope includes conceptual understanding and technical reasoning related to forces and moments in rigid bodies.

Discussion Character

  • Conceptual clarification, Debate/contested, Technical explanation

Main Points Raised

  • One participant defines the moment of a force as the turning effect created by the force about a point, emphasizing the relationship between force magnitude and perpendicular distance.
  • Another participant argues that a moment can exist relative to a point within a hollow body, suggesting that the point itself is unaffected and serves merely as a reference.
  • A different viewpoint states that the principle of moments applies to rigid bodies, indicating that moments can be calculated about any point regardless of whether the force affects that point.
  • One participant posits that the location of the point matters only in relation to the line of action of the force, drawing an analogy to the Earth's rotation and the continuous existence of rotational forces experienced by its particles.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between force and the point of reference for moments. There is no consensus on how a force can create a moment without contact, and multiple competing interpretations remain unresolved.

Contextual Notes

Some statements depend on specific definitions of force and moment, and the discussion does not resolve the implications of these definitions on the overall understanding of the topic.

RoughRoad
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I just read that moment of a force about a point is the turning or twisting effect of the force about that point.

Moment of a force= magnitude of force*perpendicular distance between the line of action of force and the point


So how can force affect that point without even coming in contact with it?
 
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It doesn't.

Consider a hollow body and take a moment relative to a point within the body.
The moment makes the body turn, but the point it's relative to is unaffected.
It is just a point of reference.
 
The principle of moments only applies to rigid bodies like levers, wheels etc.
But you can calculate the actual moments about any point you like. The force needn't actually "affect" the point.
 
yes,
it doesn't matter
where the point lies but it maters only whether the point is in line of action of that force or not?
and,
it's similar case is our Earth is rotating right about it's line of action continuously so, the rotational force do exist continuously and the particles of earth(us) also experiencing thee force.
 

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