Invariance of Newton's second law

1. Oct 24, 2005

Emanuel84

Is someone able to proove the invariance under Galilean transformations of F=dp/dt within a system of variable mass? In particular is the momentum invariant? i.e. p=p', as Goldstein states? Please answer me!

2. Oct 24, 2005

pervect

Staff Emeritus
Do you have Goldstein? I think he proves this in the text. Online, try looking up Noether's theorem (and in Goldstein, too for that matter)

http://math.ucr.edu/home/baez/noether.html

Note that you need to know that your forces are derived from a Lagrangian to prove this is true, this is equivalent to assuming Hamilton's principle of least action.