Question

why moment of inertia is not fixed?

Answer 1

This is because inertia depends on the external force.

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Answer 2

Moment of inertia is not fixed as it depends on shape of object(basically mass distribution),orientation of the axis ,position of axis of moment of inertia. For example same mass of ring and disc have different MOI ring has MR^2 while disc has 1/2MR^2.


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