Where Does the Formula p=mv Originate From in Physics?

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SUMMARY

The formula for momentum, expressed as p = mv, originates from classical mechanics and is fundamentally empirical. Momentum is defined as a variable that describes the physical state of a particle, with its value being zero when the particle is at rest in an inertial reference system. According to Newton's second law, the change in momentum is directly related to the forces acting on the particle. At quantum and relativistic levels, this classical definition is superseded by the concept of canonical momentum as described in Hamiltonian mechanics.

PREREQUISITES
  • Understanding of classical mechanics principles, particularly Newton's laws.
  • Familiarity with the concept of momentum in physics.
  • Knowledge of Hamiltonian mechanics and canonical momentum.
  • Basic grasp of inertial reference systems.
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  • Study Newton's laws of motion in detail.
  • Explore the concept of canonical momentum in Hamiltonian mechanics.
  • Research the differences between classical and quantum momentum.
  • Examine the implications of momentum in relativistic physics.
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Students of physics, educators teaching classical mechanics, and researchers interested in the foundations of momentum in both classical and modern physics.

Cheman
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What exactly IS momentum? How do we arrive at the formula "p= mv"? Where does that formula come from - is it purely empirical or is there something more meaningful to it?

Thanks. :smile:
 
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Cheman said:
What exactly IS momentum? How do we arrive at the formula "p= mv"? Where does that formula come from - is it purely empirical or is there something more meaningful to it?

Thanks. :smile:

It's one of the fundamental concepts in physics.It's introduced purely experimental.It is,alonside position,one variable which describes,at classical level,the physical state of the particle.According to the first Newton's law,an isolated particle has a specific fixed momentum.If it's at rest in an inertial reference system,its momentum is zero.If not,not.Changes of momentum automatically imply that the particle suffered an interraction (and viceversa)described at classical level by forces.Newton's second law should always be stated mathematically by:\frac{d(m\vec{v})}{dt} is equal to the vector sum of all forces acting on the particle.It can be interpreted via "cause-effect logics".
The definition u gave belongs only to the realm of classical (nonrelativistic)mechanics of pointlike particles in the Newton's approach.
At quantum + relativistic level,it's not valid anymore,because both theories deal with other notion of momentum,the canonical momentum (see Hamilton formalism of classical dynamics).

Regards,

Daniel.
 
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