Euler' s equations and tau = zero?

[student1938]

A uniform circular disk of mass m and radius a is constrained to rotate with constant angular speed omega abotu an axis making an angle theta with the disk' s axis of symmetry. Find the magnitude and direction of the angular momentum L and the torque tau exerted on the disk by its supporting axis. Give a physical interpretation of your answer.

We had doen a similar thing in class but the professor assumed that tau = 0 for some reason and then went on to get some precession related stuff. Do I follow the same steps(using Euler' s equations as he did) and if so what is the significance of the tau being zero?

 

[student1938]

Come on ..something anything would be great.

 

[ahrkron]

It would be useful if you post some of what your professor did (in particular: what was the statement of the problem he solved in class?, and what is this "tau" you mention?). The most info you give, the better.

 

[student1938]

The assumption was that tau = 0 and from there, the Euler equations were solved and they gave a frequency. Along with that there was a few steps to show what omega was and that was about it really, I did not see anything special besides that.