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Homework Help: Gyro question

  1. Aug 19, 2009 #1

    Read the picture please. My question is: where does the work done by torque T go and is the equation on left all right? No gravity, no friction.
    Last edited by a moderator: Aug 19, 2009
  2. jcsd
  3. Aug 19, 2009 #2
    Come on man, how come this problem be an Introductory Physics homework?
  4. Aug 19, 2009 #3
    Trying showing some work and explaining the situation a little. What you're given and such. All i see is a spinning disc with some 'spin' and torque.
  5. Aug 19, 2009 #4

    The "spinning disk" is a gyro spinning at angular speed omega and the moment of inertia about this spinning axis is I.

    A torque T is applied on the gyro and perpendicular to spin axis, the torque is also called gyroscopic torque.

    The rotation caused by torque T is theta. theta dot is derivative of theta, theta dot dot is second order derivative of theta. Moment of inertia about theta axis is Iy (perpendicular to spin axis).

    My question: is the equation on the left of the picture all right? The work done by T (gyroscopic torque) contributes to what, where it goes finally?
  6. Aug 19, 2009 #5
    The work done by T torque is the... κινητικη ενεργεια... kinimatecal or mobility energy how you call it. If I understood correct the T at first stops the gyro THEN makes it move with a different dirrection. So at first it has negative work (takes from it's energy because of the movement) and after the stop it gives to it.
  7. Aug 19, 2009 #6
    Not that case. The spinning gyro is at rest at beginning; then a torque is applied. What happens? If torque is dismissed after a while, then what?
  8. Aug 20, 2009 #7
    I figured it out.
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