1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

F = del(p.E) and F = (p.del)E are equivalent

  1. Nov 13, 2013 #1
    Question: In the electrostatic case, the expressions F = del(p.E) and F = (p.del)E are equivalent:

    I am having trouble with how to show they are equivalent

    In the second equation, I expanded it out to give F= px (dE/dx) + py (dE/dy) + pz(dE/dz)

    Any help as to how to do this would be much appreciated

  2. jcsd
  3. Nov 13, 2013 #2

    Meir Achuz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    You have to use the vector differential operator equation
    [tex]\nabla({\bf p\cdot E)=p\times(\nabla\times E)+(p\cdot\nabla)E}[/tex],
    and curl E=0.
    Last edited: Nov 13, 2013
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook