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Homework Help: Lorentz Force

  1. May 4, 2010 #1
    1. The problem statement, all variables and given/known data
    Consider a particle of mass m that carries a charge q. Suppose that the particle is under the influence of both an electric field E and a magnetic field B so that the particle's trajectory is described by the path x(t) for a[tex]\leq[/tex]t[tex]\leq[/tex]b. Then the total force acting on the particle is given in mks units by the Lorentz force,

    F=q(E + vxB),

    where v denotes the velocity of the trajectory.

    a) Use Newton's second law of motion (F=ma) to show that

    ma.v = qE.v (dot products)

    2. Relevant equations



    3. The attempt at a solution
    Tried distributing to help make sense of the problem, but didn't do much for me:
    ma = qE + q(vxB)
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. May 5, 2010 #2

    gabbagabbahey

    User Avatar
    Homework Helper
    Gold Member

    Take the dot product of your equation with v and use an appropriate vector identity to simplify it.
     
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