Torque T & Its Work: No Gravity, No Friction

[kyiydnlm]

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.

 

[kyiydnlm]

Come on man, how come this problem be an Introductory Physics homework?

 

[mg0stisha]

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.

 

[kyiydnlm]

Sorry.

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?

 

[ScubaDive]

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.

 

[kyiydnlm]

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?

 

[kyiydnlm]

Solved!
I figured it out.