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Homework Help: Mechanics: Degrees of freedom (extremely simple)

  1. Jun 4, 2009 #1
    1. The problem statement, all variables and given/known data
    A particle slides along a wire which is rotating at a constant angular velocity w. In polar coordinates the equation of constraint is :

    theta' - w = 0 OR theta - wt = 0. *

    What is the equation of constraint in cartesian coordinates?


    2. Relevant equations



    3. The attempt at a solution
    Is it:

    wx - y' = 0 * ???

    *all primes are derivatives wrt t.

    Thanks in advance, I know it's basic but I've hit a wall and have been looking at it for way longer than is healthy...
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Jun 4, 2009 #2

    cepheid

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    Gold Member

    Can't you just do a coordinate transformation from polar to cartesian? How is theta defined in terms of x and y?
     
  4. Jun 5, 2009 #3
    sin(theta) = y/r and cos(theta) = x/r etc.

    It's not that simple is it? I could cos or sin both sides of theta = wt but the I'll get something that looks like:

    y/r = sin(wt)...
     
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