Point of Reference for Conservation of Angular Momentum

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Discussion Overview

The discussion revolves around the conservation of angular momentum and the choice of point of reference (p.o.r.) in analyzing a system. Participants explore whether the same p.o.r. must be used before and after an event or if different p.o.r.s can be applied, particularly in relation to the total linear momentum and force in the system.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant suggests that the same point of reference should be used if the total linear momentum is non-zero, implying that angular momentum can be conserved with respect to one reference point while not being conserved with respect to another if the total force is non-zero.
  • Another participant reiterates that if the total linear momentum is zero, angular momentum is independent of the reference point, and similarly, if the total force is zero, the torque is independent of the reference point.
  • Several participants request further clarification and examples to better understand the concepts discussed.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of using the same point of reference, with some asserting it is required under certain conditions, while others seek clarification on these conditions. The discussion remains unresolved as participants continue to seek explanations.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about the conditions under which angular momentum is conserved and the dependency on the definitions of linear momentum and force.

Who May Find This Useful

This discussion may be useful for students and individuals interested in understanding the principles of angular momentum conservation and the implications of reference points in physics.

angelatan
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When analyzing the conservation of angular momentum of a particular system, should we use the same p.o.r. before and after or can we use different p.o.r.'s? As far as I know, we should always use the same reference, but sometimes I see several solutions that use different references in my textbook.

Thank you for your help, and pardon my awkward English
 
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You need to use the same point of reference if the total linear momentum is non-zero. In the same fashion, angular momentum can be preserved with respect to one reference point while not being conserved with respect to another if the total force is non-zero.

If the total linear momentum is zero, the angular momentum is independent of the reference point. If the total force is zero, the torque is independent of the reference point.
 
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Orodruin said:
You need to use the same point of reference if the total linear momentum is non-zero. In the same fashion, angular momentum can be preserved with respect to one reference point while not being conserved with respect to another if the total force is non-zero.

If the total linear momentum is zero, the angular momentum is independent of the reference point. If the total force is zero, the torque is independent of the reference point.

Can you please explain it further?
 
Quantum Aravinth said:
Can you please explain it further?
Not unless you point out what parts you have problems with.
 
Orodruin said:
Not unless you point out what parts you have problems with.

I was entirely confused,
Can you please explain it with a simple system? Be it any system
 

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