1. Not finding help here? Sign up for a free 30min 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!

How is the Force related to Energy

  1. Oct 21, 2011 #1
    1. The problem statement, all variables and given/known data

    I'm confused as to how he makes the conclusion for the last portion of the question.

    2. Relevant equations



    3. The attempt at a solution

    I would have had the following thought process,

    [tex]\vec{E_{2}} = 0 = q\vec{F_{2}}[/tex]

    [tex]q \neq 0[/tex]

    [tex]\Rightarrow \vec{F_{2}} = 0[/tex]

    Is this incorrect?

    If so, where's the math behind his answer? I'm just not seeing it.
     

    Attached Files:

    Last edited: Oct 21, 2011
  2. jcsd
  3. Oct 23, 2011 #2

    Redbelly98

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Well, the fixed voltage and charges (on the upper & lower plates) imply that the potential energy stored in the capacitor is a constant.

    Your professor is using the relation [itex]F = - \nabla \cdot U[/itex] to show that the constant potential implies zero force.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: How is the Force related to Energy
Loading...