Express torque as a function of angular velocity

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
4 replies · 2K views
Catalyst971
Messages
1
Reaction score
0
I am strugglin with this step in my assignment. I am dealing with a centrifuge with a known moment of inertia. I should write the expression for a torque of the motor and express it as a function of angular velocity. Can you help me please?
 
on Phys.org
:welcome: Next time, please fill out the Homework template. I will notify the mentors that you need to do this next time, and I think your post will be ok this time.
The equation you need is torque ## \vec{\tau}=\frac{d \vec{L}}{dt}=I \, (\frac{d\vec{\omega}}{dt}) ##, where vector ## \vec{L} =I \, \vec{\omega} ## is the angular momentum, and ## I ## is the moment of inertia about the axis of rotation. ## \\ ## Note:## \frac{d \vec{\omega}}{dt}=\frac{\Delta \vec{\omega}}{\Delta t}##. ## \\ ## Since it is basically a rotation about the z-axis, you can ignore the vectors in these equations and write ## \tau_z=I \, (\frac{\Delta \omega_z}{dt}) ##, so that torque ## \tau=I \, (\frac{\Delta \omega}{\Delta t}) ##, where ## \omega=\frac{2 \pi}{T}=(2 \pi) ## x (number of revolutions per second)=angular velocity (in radians per second), where ## T ## is the period of one revolution.
 
Last edited:
Catalyst971 said:
write the expression for a torque of the motor and express it as a function of angular velocity.
That does not quite make sense. Torque is related to angular acceleration. Please quote the task exactly as given to you.
 
Charles Link said:
@haruspex Torque is a function of the derivative of the angular velocity w.r.t. time. I think we are working with a beginner here, who might not know what a derivative is. Please see my post 2 above.
I would still like to to see the verbatim statement of the assignment.