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Homework Help: Finding Force From Potential Energy

  1. Nov 19, 2011 #1
    1. The problem statement, all variables and given/known data
    The potential energy of two neutral molecules may be modelled using the Lennard Jones potential,
    [tex]U(x)=U_0(\frac{\sigma^{12}}{x^{12}} - \frac{\sigma^6}{x^6})[/tex]
    where [itex]U_0[/itex] and [itex]\sigma[/itex] are positive constants and [itex]x[/itex] is the distance between the two molecules.

    a) Find the force at an arbitrary point x ?

    2. Relevant equations

    conservative forces and potential energy

    3. The attempt at a solution
    [tex]F(x) = -\frac{dU}{dx}= U_0(12\frac{\sigma^{12}}{x^{13}} - 6\frac{\sigma^6}{x^7})[/tex]

    Is my answer correct ?
  2. jcsd
  3. Nov 19, 2011 #2


    User Avatar

    Staff: Mentor

    Looks fine.
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