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Homework Help: Urgent I really need help please!

  1. Oct 3, 2004 #1
    Urgent!! I really need help please!

    Sorry for posting this question again. Lemme try to rephrase my question if it helps :frown: . Please help me get started on this question. I am really stuck and time is running out!! :cry: I don't want the answer, I just need some pointers to get me going and headed in the right direction.

    A particle moves in an inverse cubic, central, conservative force field. The force is
    F = -Amr^-3,

    where A = some constant,
    m = mass of particle (pt. mass)
    r = distance

    I know that the angular momentum L (its 3 components) are conserved under a central force. The total energy is also conserved since the force is conservative.

    L = m r^2 θ'
    E = (1/2) m (r')^2 + (1/2) m r^2 θ'^2 + V(R)
    The 2 equations above are written in polar coordinate form.

    Is V(R) = - / F? (/ = integral...sorry) :frown:

    How should I go about in describing the possible orbits of a particle moving under the influence of such a force? I have to consider the following cases: E = 0, E < 0, and E > 0, for non-zero angular momentum cases.

    I need some desperate guidelines to get me started. Please give some advices. Thanks in advance! :redface:
  2. jcsd
  3. Oct 3, 2004 #2
    What is V(R)? If you need to display integrals or other math. symbols, use LaTex.
  4. Oct 3, 2004 #3
    V(R) is the potential as a function of R.
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