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Homework Help: Work with circular motion

  1. Jan 11, 2008 #1
    1. A 62 kg woman stands at the rim of a horizontal turntable with a moment of inertia of 540 kg·m2 and a radius of 2.1 m. The system is initially at rest, and the turntable is free to rotate about a frictionless vertical axle through its center. The woman then starts walking clockwise (when viewed from above) around the rim at a constant speed of 1.5 m/s relative to the Earth. If it helps the angular speed of the turntable is .361667 rad per second. How much work does the woman do to set the system in motion?

    2. KErotational=(1/2)IW^2
    Angular velocity = W = Vt/R

    3. KErotational=1/2(62*2.1)(1.5/2.1)^2
    Work=Change in KE
  2. jcsd
  3. Jan 12, 2008 #2

    Shooting Star

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    Was there any external torque on the system? Does that suggest anything?
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