Attacking Einstein (and other pursuits)

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Discussion Overview

The discussion revolves around the nature of physical constants, their significance, and the relationships between momentum, mass, and velocity in physics. Participants explore the concept of parameter analysis and question the foundations of various physical terms and units.

Discussion Character

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

Main Points Raised

  • One participant questions whether there is a field in physics that studies the significance of arbitrary constants and their magnitudes, suggesting a need for a theoretical foundation for physical terms.
  • Another participant argues that while constants may seem arbitrary, it is the units of measurement that are arbitrary, and changing the speed of light reflects a change in the system of units.
  • A third participant mentions that fundamental constants are determined by many overlapping measurements and refers to a detailed source for further information.
  • There is a discussion about the relationship between momentum and velocity, with one participant asserting that the proportionality exists, while another points out that the initial question contained incorrect units.
  • One participant emphasizes that the relationship between variables in equations can be manipulated while maintaining proportionality, illustrating this with an example involving momentum and velocity.

Areas of Agreement / Disagreement

Participants express differing views on the nature of physical constants and their significance, with no clear consensus reached on the foundational questions raised. The relationship between momentum and velocity is also discussed with some agreement on proportionality but differing interpretations of the original question.

Contextual Notes

Some statements contain assumptions about the definitions of physical terms and the context of measurements, which remain unresolved. The discussion also highlights potential misunderstandings regarding the manipulation of equations and units.

Gorn
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Hello...

I have heard that the speed of light is 300,000km/s. Planks constant is another number and so on and so on and so on.

a lot of these numbers seem to be very 'arbitrary' figures... Is there a subject in physics called "parameter" analysis where the various arbitrary numbers and constants in physics are studied to give some understanding or reason for their magnitude?

Also, is there another area in physics that provides principled or theoretical or a logical foundation for the various terms in physics like ...m/s, kg/m/s etc.etc.etc. that were introduced in physics to formulate various theory's. Sorry.. a bit of a vague question.

* In the equation P=mv (which is the equation for momentum)...if I switch the variables around I get M=P/v...Does this equation mean that if there is a change in momentum there is a "direct - and exactly porportional change in velocity? Eg. If P= 5m/s v will equal 5m/s?
Thank you for any and all answers.
Bye
G.
 
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The constants are not arbitrary, our units of measurement are the arbitrary units. You can set the speed of light to whatever you want, ~3.0e8 m/s or 1 something/something. But this reflects a change in your system of units.

The change in momentum is equal to force via Newton's laws. Force is the product of mass and acceleration, the latter describing the change in velocity over time.
 
The fundamental constants are overdetermined by many overlapping partially correlated precision measurements. A detailed discussion of the latest comprehensive least-squares fit can be found at

http://physics.nist.gov/cuu/Constants/RevModPhys_80_000633acc.pdf

A summary of the fundamental constant values can be found on pg 85 of the pdf.

Bob S
 
Gorn said:
In the equation P=mv (which is the equation for momentum)...if I switch the variables around I get M=P/v...Does this equation mean that if there is a change in momentum there is a "direct - and exactly porportional change in velocity? Eg. If P= 5m/s v will equal 5m/s?

Your units are wrong, but the proportionality you refer to is there.

For example, if an object has a velocity of 9 m/s and a momentum of 100 kg m/s, then for the same object, its mass unchanged, if its new velocity were 27 m/s, then its new momentum would be 300 kg m/s.

This isn't a question about physics but a question about how to use fractions. In general, to say that A/B = some constant means that it's equally true to write that 3A / 3B is the same constant, or 94A / 94B = the same constant.
 

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