Why there is different moment of inertia with respect to point P about which a rigid body is moving around a circle with some velocity and spinning about its own axis compared to the one which is just moving around a circle about point P and not spinning about it's own axis.

Let's say the rigid body is a circular disc of radius R and Mass M and it's centre of mass is revolving around cirlce of radius 'L'.

Need some clarification.


closed as unclear what you're asking by John Rennie, Jon Custer, ZeroTheHero, Kyle Kanos, stafusa Feb 19 at 21:28

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  • $\begingroup$ Hi Amir and welcome to the Physics SE! Please note that we don't answer homework or worked example type questions. Please see this page in the site help for more on what topics you can ask about here. $\endgroup$ – John Rennie Feb 18 at 17:20

Moment of inertia depends on the distribution of mass around the rotating axis.
In the former case, the body is rotating in it's own axis. Thus distribution of mass with respect to it's own axis should also be considered. Latter case, body is rotating with respect to P. Thus Distribution of mass with respect to P only should be considered.

  • $\begingroup$ How's that? What is the definition cuz in my books it doesn't matters $\endgroup$ – Amir RAZA Feb 19 at 9:01

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