Definition of Parallel-axis theorem

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The parallel-axis theorem expresses the moment of inertia (I) about an axis a distance (h) from the center of mass as the sum of the moment of inertia about the center of mass (Icom) and the product of the mass (M) and the square of the distance (h^2). In this equation, Icom represents the moment of inertia about the center of mass axis, while I accounts for the additional inertia due to the offset from the center of mass. The theorem highlights how mass distribution affects rotational inertia when shifting axes. Understanding these terms is crucial for analyzing rotational dynamics in physics. The discussion clarifies the physical significance of each component in the theorem.
Duane
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What is the physical meaning of each term in the parallel-axis theorem?


I=I com +Mh^2
 
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Duane said:
What is the physical meaning of each term in the parallel-axis theorem?


I=I com +Mh^2
Not sure what you mean by 'physical' meaning, but:
I = moment of inertia about some axis a distance 'h' from the center of mass
Icom = moment of inertia about some axis (parallel to the other) passing through the center of mass
M = mass of object
h = distance between those two parallel axes

You can think of it as the sum of the moment of inertia about the center of mass and the moment of inertia of the total mass (considered as a point mass) about the axis in question.
 
Duane said:
What is the physical meaning of each term in the parallel-axis theorem?


I=I com +Mh^2
Icom is the moment of inertia of an object about an axis through the centre of mass. I is the moment of inertia of the object about an axis that is parallel to the axis through the centre of mass (com) and separated from it by a distance h. M is the mass of the object.

AM
 
Thanks, that helped a lot!
 

Thread 'Reference frames, center of rotation, etc'

Topic about reference frames, center of rotation, postion of origin etc Comoving ref. frame is frame that is attached to moving object, does that mean, in that frame translation and rotation of object is zero, because origin and axes(x,y,z) are fixed to object? Is it same if you place origin of frame at object center of mass or at object tail? What type of comoving frame exist? What is lab frame? If we talk about center of rotation do we always need to specified from what frame we observe?
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