Class_31new - 1 PHYS809 Class 31 Notes Momentum and the...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 PHYS809 Class 31 Notes Momentum and the electromagnetic stress tensor We now consider conservation of momentum. Let P part be the total momentum of all the particles in a fixed volume V . Using the Lorentz force on a single particle of charge q , ( ) , q = + F E v B (31.1) the rate of change of the momentum is 3 . part V d d x dt = + P E J B (31.2) Using Maxwells equation to eliminate the charge and current densities, this is 3 . part V d d x dt t = + - P D E D H B (31.3) Using the identity ( ) , t t t - = - + D B B D B D (31.4) we get ( ) ( ) 3 . part V d d x dt t t = + - + P B E D H B D B D (31.5) Using the Maxwell equations 0, t + = B E (31.6) and 0, = B (31.7) we get ( ) ( ) 3 3 . part V V d d d x dt dt d x + = + - - P D B E D H B B H D E (31.8) We associate the second term on the left side of the equal sign with the rate of change of momentum of the electromagnetic field. The density of electromagnetic momentum is then the electromagnetic field....
View Full Document

This note was uploaded on 12/02/2011 for the course PHYS 809 taught by Professor Macdonald during the Fall '11 term at University of Delaware.

Page1 / 4

Class_31new - 1 PHYS809 Class 31 Notes Momentum and the...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online