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Homework Help: Uniform Circular Motion in a Watch

  1. Mar 28, 2012 #1
    1. The problem statement, all variables and given/known data

    The second hand on a watch has a length of 4.5mm and makes one revolution in 60s. What is the speed of the end of the second hand as it moves in uniform circular motion?

    2. Relevant equations


    3. The attempt at a solution

  2. jcsd
  3. Mar 28, 2012 #2
    speed = distance/time
    How far does the end of the hand move in 1 revolution?
    How long does that take?
  4. Mar 28, 2012 #3
    The equation you need to use here is:
    v = ωr
    Where ω is angular velocity.

    The angular velocity is given by:
    ω = Δθ / Δt

    Thus the angular velocity of the second hand is known from the statement of your problem. Hope this helps.
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