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Homework Help: Help Finding path of a particle with an intial position and initial velocity

  1. May 13, 2012 #1
    Hi everyone,

    I am having trouble finding the answer to a homework problem. I don't seem to understand what the question is exactly asking for. The problem is:

    find the path of a particle with an initial position 10er + 1.0eϴ and an initial velocity 0.1er + 0.8eϴ
    Last edited: May 13, 2012
  2. jcsd
  3. May 13, 2012 #2
    Have you considered using the kinematics for cylindrical coordinates?
  4. May 13, 2012 #3
    the equations I am thinking about using are

    Cylindrical coordinates: r, ∅, z
    x=rcos∅ y=rsin∅

    Spherical Coordinates: r, θ, ∅
    x=rsinθcos∅ y=rsinθsin∅ z=rcosθ

    I also know an equation for velocity as v=[itex]\dot{r}[/itex]er + r[itex]\dot{θ}[/itex]eθ

    I'm still very confused as to what to do with all these equations to find the path of the particle. Please Help.
    Last edited: May 13, 2012
  5. May 13, 2012 #4
    Those equations look like they are for converting from Cartesian coordinates to cylindrical / spherical coordinates.

    Try looking around in your book for the kinematic equations in cylindrical / spherical form. If they aren't in your book you could try going to this link


    and try looking for them by Crtl+F and typing in what you're looking for.

    I haven't ever worked with those coordinate systems and kinematic equations before, otherwise I would be more helpful.
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