0
$\begingroup$

I believe $T=I_{cm}\alpha$, where $I_{cm}$ is the moment of inertia about centre of mass and $\alpha$ is the angular acceleration. But do we take $I_{cm}$ even if the torque has been taken about a point which is not the centre of mass? Would we then apply parallel axis theorem and find the new moment of inertia and use it in our equation? If no, then why not?

$\endgroup$
  • 1
    $\begingroup$ The simplest equation of motion for rotation is $T=I\dot{\omega}$ where $I$ is the moment of inertia around the axis of rotation and $T$ is the torque around the axis of rotation. $\dot{\omega}$ is the angular acceleration resulting. $\endgroup$ – Gert Nov 14 '15 at 14:34
0
$\begingroup$

The moment of inertia is definitely affected by where the axis of rotation is located. To find the torque required to rotate an object where the axis of rotation is not through the center of mass, you definitely need to use the parallel axis theorem. If you intend to rotate a real-world object in such a fashion, expect a lot of "wobble" in the object if you intend to rotate it at any substantial angular velocity.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.