2
$\begingroup$

While I was trying to find out the mass moment of inertia of an elliptical ring I got struck and could not think about as to what I must do. I tried integrating but the radius keeps changing from semi major to semi minor. I have also tried using the perpendicular axis theorem but again the maths is starting to go over my head. and despite all of this I haven't come any closer to anything that remotely looks like a solution to my problem.

I am also unable to guess as for what kind of piece of the ellipse shaped ring I should take so as to integrate them to find out the moment of inertia

$\endgroup$

closed as off-topic by Bill N, user36790, ACuriousMind, Jon Custer, Qmechanic Sep 24 '16 at 14:21

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Homework-like questions should ask about a specific physics concept and show some effort to work through the problem. We want our questions to be useful to the broader community, and to future users. See our meta site for more guidance on how to edit your question to make it better" – Bill N, Community, ACuriousMind, Jon Custer, Qmechanic
If this question can be reworded to fit the rules in the help center, please edit the question.

  • 1
    $\begingroup$ Keep working at it. It won't help you for us to do it for you. And about which axis are you trying to calculate it? $\endgroup$ – Bill N Sep 23 '16 at 17:24
  • $\begingroup$ Interesting question. Please show your work. For some shapes the integral will be difficult. $\endgroup$ – sammy gerbil Sep 23 '16 at 22:49
  • $\begingroup$ Probably not that difficult actually. You can work it out from the area moment of inertia for an ellipse by differentiating wrt $a$ and $b$, or subtracting MI for ellipse with axes $(a,b)$ from one with axes $(a+\delta a, b+(b/a)\delta a)$. $\endgroup$ – sammy gerbil Sep 24 '16 at 14:33