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Homework Help: Classical mechanics problem

  1. Sep 12, 2011 #1
    1. The problem statement, all variables and given/known data
    A particle has a velocity u = -V0 i + V0 j and position (d,0) at t=0. At any time t its position in polar coordinates is (r,theta) and velocity V = V0 cos theta i + (V0-V0sin theta) j. At t =t, angular velocity of the particle at the origin will be -----------------

    2. Relevant equations

    angular velocity w = d(theta)/dt

    3. The attempt at a solution

    actually i didnt understand the question itself. why these two velocities are given.
  2. jcsd
  3. Sep 13, 2011 #2


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    Staff Emeritus
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    The particle is moving in two dimensions.

    There is vx = dx/dt and vy = dy/dt. Now if one writes x = r cos θ, and y = r sin θ, then try dx/dt and dy/dt, what is the result?

    Also think about ω = dθ/dt, and θ = ωt + θo.

    Is ω costant? Is u constant?
  4. Sep 13, 2011 #3
    i feel that U is a constant as no variables appear in the expression for u. nothing is mentioned about w in the question. the answer should be v0(cos theta)/r.
    the radial velocity of the patricle about the origin should be -V0(1-sin theta)
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