Friday, July 8, 2016

symmetry - Definitions and usage of Covariant, Form-invariant & Invariant?


Just wondering about the definitions and usage of these three terms.


To my understanding so far, "covariant" and "form-invariant" are used when referring to physical laws, and these words are synonyms?


"Invariant" on the other hand refers to physical quantities?


Would you ever use "invariant" when talking about a law? I ask as I'm slightly confused over a sentence in my undergrad modern physics textbook:



"In general, Newton's laws must be replaced by Einstein's relativistic laws...which hold for all speeds and are invariant, as are all physical laws, under the Lorentz transformations." [emphasis added]


~ Serway, Moses & Moyer. Modern Physics, 3rd ed.




Did they just use the wrong word?




No comments:

Post a Comment

classical mechanics - Moment of a force about a given axis (Torque) - Scalar or vectorial?

I am studying Statics and saw that: The moment of a force about a given axis (or Torque) is defined by the equation: $M_X = (\vec r \times \...