Path: ...!weretis.net!feeder8.news.weretis.net!fu-berlin.de!uni-berlin.de!news.dfncis.de!not-for-mail From: ram@zedat.fu-berlin.de (Stefan Ram) Newsgroups: sci.physics.research Subject: The momentum - a cotangent vector? Date: 7 Aug 2024 06:54:34 GMT Organization: Stefan Ram Lines: 16 Approved: hees@itp.uni-frankfurt.de (sci.physics.research) Yes, this is a question for all you mathematical physics folks out there! Message-ID: X-Trace: news.dfncis.de vSpEOhn9z/8HMSMlflER8woG9OY5BP9qeLM3VBa4DtcLiLA0srAcnQeVNDoj1wGxAe Cancel-Lock: sha1:VCYM4HDnxmzPxO3SrTABIvO/ADM= sha256:CwkuNUUF2LozuApDW0wnQUtMxw/ktp3JujLLZ2WhIFw= Bytes: 1425 In mathematical classical mechanics, the momentum is a cotangent vector, while the velocity is a tangent vector. I don't get this! A cotangent vector maps a tangent vector to a scalar (real number). That much I know. But since when is the momentum (in physics) a function that maps a velocity to a real number, and what is the physical interpretation (meaning) of that real number? Using the Lagrange function L, the momentum is p = dL/dq', where d is the sign for the partial derivative (this newsgroup does not do Unicode) and q' is a "q" with a dot above. How can I see that (given that q' is a tangential vector) p is a cotangential vector?