The effect of a field on a particle depends on the particle velocity?

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Discussion Overview

The discussion centers on the relationship between a vector field's effect on a particle and the particle's velocity. Participants explore whether the change in momentum of a particle due to a force depends on its speed at a given position, the time interval during which the force acts, and the implications of these factors in the context of D'Alembert's principle and inertial forces.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions if the effect of a vector field on a particle's momentum depends on the particle's speed at that position and whether this is related to the time interval during which the force acts.
  • Another participant agrees that the effect can depend on speed, citing the example of a charged particle in a magnetic field and the Lorentz force.
  • There is a discussion about the relationship between time interval and velocity, with one participant stating that dt can be expressed as dx/v, which is defined by the velocity.
  • A participant expresses uncertainty about the meaning of 'inertial force of the particle' and seeks clarification on D'Alembert's principle.
  • Further inquiries are made about the mathematical correctness of the relationship dt=dx/v, with a note that v=0 presents an exception.
  • One participant requests references or examples to better understand the concepts discussed.

Areas of Agreement / Disagreement

Participants generally agree that the effect of a field on a particle can depend on its speed, but there is no consensus on the implications of this relationship or the interpretation of related concepts such as inertial forces and D'Alembert's principle.

Contextual Notes

The discussion includes assumptions about the definitions of terms like 'inertial force' and the conditions under which the relationship dt=dx/v holds true, particularly when velocity approaches zero.

ahmadphy
Assume there is a force (vector field) on the space .....does the effect of this field on the particle(the change of momentum) at some position depend on the speed at that position? And is it related to the time interval dt the particle experiences this force ? Can i say dt=dx/v? And is that related to the inertial force of the particle due its kinetic energy?
 
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Hello @ahmadphy ,
:welcome: ## \qquad## !​
ahmadphy said:
Assume there is a force (vector field) on the space .....does the effect of this field on the particle(the change of momentum) at some position depend on the speed at that position?
That is possible, yes. Example: charged particle in a magnetic field. Google Lorentz force.

ahmadphy said:
And is it related to the time interval dt the particle experiences this force ? Can i say dt=dx/v? And is that related to the inertial force of the particle due its kinetic energy?
The force itself does not depend on ##{\rm d} t##.
You can say ##{\rm d }t={\rm d} x/v## because that's the definition of ##v##.
[ edit ] mathematicians may frown on this...I don't know what 'the inertial force of the particle' means.

##\ ##
 
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BvU said:
Hello @ahmadphy ,
:welcome: ## \qquad## !​

That is possible, yes. Example: charged particle in a magnetic field. Google Lorentz force.The force itself does not depend on ##{\rm d} t##.
You can say ##{\rm d }t={\rm d} x/v## because that's the definition of ##v##.
[ edit ] mathematicians may frown on this...I don't know what 'the inertial force of the particle' means.

##\ ##
Thank you...I know lorentz force...what I want from the question is to understand d'alembert's principle and what I meant by inertial force of the particle due to its kinetic energy is that when a force acts on a moving body it will follow some path I can have the same path if I assumed the particle is at rest and transformed the kinetic energy to force then apply the same force as the situation when it was moving
 
ahmadphy said:
Thank you...I know lorentz force...what I want from the question is to understand d'alembert's principle and what I meant by inertial force of the particle due to its kinetic energy is that when a force acts on a moving body it will follow some path I can have the same path if I assumed the particle is at rest and transformed the kinetic energy to force then apply the same force as the situation when it was moving
Also when I asked if I can say that dt=dx/v is it always mathematically correct?
 
ahmadphy said:
Also when I asked if I can say that dt=dx/v is it always mathematically correct?
Well, ##v=0## requires an exception :wink:
 
ahmadphy said:
Thank you...I know lorentz force...what I want from the question is to understand d'alembert's principle and what I meant by inertial force of the particle due to its kinetic energy is that when a force acts on a moving body it will follow some path I can have the same path if I assumed the particle is at rest and transformed the kinetic energy to force then apply the same force as the situation when it was moving
I really still don't understand... Do you have a reference or an example?

##\ ##
 

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