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Homework Help: Calculating angular speed out of tangential speed

  1. Dec 6, 2008 #1
    1. The problem statement, all variables and given/known data

    A particle A is moving at constant tangential speed v1 = 2m/s on a circumference of radius r1 = 5m.
    Particle B is performing a uniform circular motion on a circumference whose radius is r2 = (2)r1.
    Find the tangential speed of v2 of particle B assuming that the angular speed w2 of particle B is twice the angular speed w1 of particle A

    2. Relevant equations
    Tangential speed at 10m from the axis point is 2 times the tangential speed at 5m from the axis.

    3. The attempt at a solution

    v1=2m/s at 5m from the axis of rotation
    IF particle B was rotating at the same angular speed....v2=4m/s
    BUT w2 = 2w1 SO v2=8m/s
  2. jcsd
  3. Dec 6, 2008 #2


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    Homework Helper

    That looks correct.

    v/r = 2/5 = ω

    2ω = 4/5

    v = ω *r = 4/5*10 = 8
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