Talk:Parallel axis theorem

Article Title

The pages parallel axis theorem and parallel axes theorem, were redirected to parallel axes rule. However, I think parallel axis theorem is more accepted, so I've made that the true page. First, this is what the name is in my physics book; second, a google search of each of these confirms this: [1] [2] [3] --JianLi 21:18, 14 October 2006 (UTC)[reply]

At least in Swedish physics coursebooks, this I = I_0 + md^2 is called Steiner's formula.

Possible Error

I am taking a course in waves and vibrations and have been assured by my physics professor that there is no parallel axis theorem for second moment of area. She says that the parallel axis theorem applies only to moment of inertia. Searching on the internet and in text books I have been unable to find references to a parallel axis theorem for second moment of area. I don't pretend to be an expert on the subject, but could someone who knows more about it look into that? Thanks. 130.15.167.195 21:18, 19 March 2007 (UTC)nasturtium86[reply]

It indeed exists. Second_moment_of_area#Parallel_axis_theorem. Just take the Classica Mechanics definition in the article and consider off diagonal elements.--Loodog 23:49, 9 July 2007 (UTC)[reply]

Proposed revisions

I would like to add sections on the parallel axis theory for the polar moment of inertia that is important for planar rigid body dynamics, and on the parallel axis theorem for spatial rigid body dynamics. Prof McCarthy (talk) 20:49, 11 October 2012 (UTC)[reply]

Variance (Probability)

Probability theory has many parallels to basic physics, expected value - center of mass, variance - moment of inertial.

I think it would be worthwhile to include a discussion about how the parallel axis theorem is equivalent to the identity var[X]=E[X²]-E[X]² Fifekm (talk) 20:21, 31 October 2023 (UTC)[reply]