- #1
SamRoss
Gold Member
- 254
- 36
I am watching Susskind's derivation of Newton's F=ma from the Euler-Lagrange equations (53 minutes in) here for which he uses the Lagrangian of kinetic energy minus potential energy. I have seen this done elsewhere as well. As far as I can tell, and please correct me if I'm wrong, the only reason to do this is because by convention we define F as the negative of the derivative of potential so subtracting potential energy in the Lagrangian will lead directly to F=ma and not -F=ma. I guess my real question is, is there any reason why we can't just change the convention of having F be equal to the negative derivative of potential energy so we would be able to write the Lagrangian as kinetic plus potential energy (as it feels like it should be)?
Last edited by a moderator: