Am I right to conclude this about mass?

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Discussion Overview

The discussion revolves around the concept of mass and its relationship with force, particularly in the context of Newton's laws of motion. Participants explore how forces interact with moving masses and the implications of these interactions in terms of work done.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant asserts that a moving mass applies a force in response to an external force acting on it, suggesting a relationship between motion and force.
  • Another participant references Newton's Third Law, indicating that forces exist in pairs and that a force on a mass implies a corresponding reaction.
  • A different viewpoint emphasizes Newton's First Law, arguing that a force exists only if there is acceleration, and questions the phrasing of "applying a force on a force."
  • A later contribution discusses the concept of work, stating that a mass on a table experiences balanced forces (downward and upward) and therefore does not perform work.

Areas of Agreement / Disagreement

Participants express differing interpretations of the relationship between force and motion, with some agreeing on the application of Newton's laws while others challenge the phrasing and conclusions drawn from the initial statements. The discussion remains unresolved regarding the implications of these interpretations.

Contextual Notes

There are limitations in the assumptions made about the nature of forces and motion, particularly regarding the definitions of work and the conditions under which forces are considered to act.

dE_logics
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When a force applies on a freely moving mass, it opposes the motion, to oppose the motion there should be a force. So we can conclude that if a mass is made to move, it applies a force on the force that applies on it
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If any moving mass is set to motion, without collapsing itself (or breaking), it can be said that the normal reaction given by the mass is equal to the force that applies on it.
 
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Yes, exactly Newton's Third Law.
 
dE_logics said:
When a force applies on a freely moving mass, it opposes the motion, to oppose the motion there should be a force.
You are saying a force on a mass exists if and only if there is an acceleration (in your terms, if "it opposes the motion"). This is Newton's First Law.

dE_logics said:
So we can conclude that if a mass is made to move, it applies a force on the force that applies on it.
It doesn't make sense to "apply a force on a force". Instead, we should say "apply a force to an object causing that force". As Pengwuino said, this is Newton's third law. I wouldn't say we can "conclude" this is true just because what you said before was true, though.
 
Ok...thanks a lot people!
 
Force without motion does no work. A mass M on a table has a downward force Mg, and the table has an equal opposing upward force -Mg, so the two forces balance , and no work is done.
 

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