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Time given angular velocity/displacement

  1. Nov 7, 2011 #1
    A gymnast is performing a floor routine. In a tumbling run she spins through the air, increasing her angular velocity from 2.90 to 5.40 rev/s while rotating through one half of a revolution. How much time does this maneuver take?

    Knowns:
    w0 = 2.9 rev/sec * 2pi rad = 18.22 rad/sec
    w = 5.4 rev/sec * 2pi rad = 33.92 rad/sec
    θ = 180?

    θ = 1/2 (w0 + w) t
    180 = 1/2 (18.22 + 33.92) t
    180 = 1/2 (52.14) t
    (/180) 180 t = 26.07 (/180)
    t = .1448

    I know this is incorrect, and would appreciate help in the right direction.
     
  2. jcsd
  3. Nov 7, 2011 #2

    gneill

    User Avatar

    Staff: Mentor

    Don't mix radians and degrees!
     
  4. Nov 7, 2011 #3
    Got it! :D

    θ = 180 deg *(pi/180) = 3.14 rad

    ω = 26.07

    θ = ωt

    which turns into

    t = θ/ω

    t = .12044
     
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