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Give an x-y equation for the path of the particle

  1. Aug 8, 2009 #1
    1. The problem statement, all variables and given/known data

    a. give unit vector in direction of r'(t)
    b. give unit vector in plane of motion which is normal to r'(t)
    c. give an x-y equation for the path of the particle

    3. The attempt at a solution

    well a. i think is just finding the unit vector but i am having trouble finding it. r'/|r'|=1/root(4w^2cos^2(wt)+9w^2sin^2(wt))*r' i dont think this i right tho because i cant cancel the sin cos squared because of not common factors... and the other 2 i have no idea, please can someone help me.
  2. jcsd
  3. Aug 9, 2009 #2
    Re: mechanics

  4. Aug 9, 2009 #3
    Re: mechanics

    See the question, it provides you that numbers. You cannot do much about it.

    b) Hint:
    r'(t).normal = 0
    . = dot

    from r(t)=(2sin(wt),3cos(wt))
    x = 2sin(wt)
    y = 3cos(wt)

    so find h(x) such that y = h(x)
  5. Aug 9, 2009 #4
    Re: mechanics

    thanks heaps!
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