Describing the second law of motion using linear momentum

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SUMMARY

The discussion focuses on the characterization of the second law of motion using linear momentum, specifically comparing the equations F=ma and F=dL/dt. The first equation is defined as a "coordinate-based equation," while the second equation, which incorporates linear momentum (L), is suggested to be more general. A key distinction is that F=ma assumes a fixed mass, whereas F=dL/dt allows for mass variation over time, leading to the formulation F=ma + (dm/dt)v. This highlights the broader applicability of the momentum-based equation.

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  • Understanding of Newton's laws of motion
  • Familiarity with linear momentum concepts
  • Knowledge of calculus, specifically derivatives
  • Basic physics terminology related to force and mass
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  • Research the implications of variable mass in dynamics
  • Study the derivation of F=dL/dt in detail
  • Explore applications of linear momentum in real-world scenarios
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Trying2Learn
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Hi! This is a very simple question regarding terms of expressions.

  1. One law of motion is: F=ma
  2. Another, using L as the linear momentum, is: F = dL/dt

If the first equation can be characterized (ignoring reference frames) as a "coordinate-based equation" (since is concerned with the second derivative of the position coordinate) (also ignoring moving reference frames, etc.)...

Then, how would one characterizes the second equation? Yes, I can see it is different, but would one say "more general?"

How would one state the difference in the formulation? "?-based equation"
 
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Trying2Learn said:
Summary:: Describing the second law of motion using linear momentum

Hi! This is a very simple question regarding terms of expressions.

  1. One law of motion is: F=ma
  2. Another, using L as the linear momentum, is: F = dL/dt

If the first equation can be characterized (ignoring reference frames) as a "coordinate-based equation" (since is concerned with the second derivative of the position coordinate) (also ignoring moving reference frames, etc.)...

Then, how would one characterizes the second equation? Yes, I can see it is different, but would one say "more general?"

How would one state the difference in the formulation? "?-based equation"

There is one important difference. ##F = ma## explicitly assumes a fixed mass. Whereas ##F = \frac{dL}{dt}## can be written as ##F = \frac{d}{dt}(mv)## and then you can have an argument about whether this includes the case where mass varies with time. I.e. whether you can write ##F = ma + \frac{dm}{dt}v## and what this means.
 
Trying2Learn said:
... using L as the linear momentum...
..."?-based equation"
1) It doesn't matter how you call it
2) You say right there what it is based on
 
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