Define: (i) Moment of Inertia (ii) Radius of Gyration

Define: (i) Moment of Inertia (ii) Radius of Gyration
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1 Answer

Answer :

i) Moment of Inertia: Moment of Inertia of a body about any axis is equal to the product of the area of the body and square of the distance of its centroid from that axis. 

OR 

Moment of inertia of a body about any axis is defined as the sum of second moment of all elementary areas about that axis. 

ii) Radius of Gyration: Radius of Gyration of a given area about any axis is that distance from the given axis at which the entire area is assumed to be concentrated without changing the M. I. about the given axis. 
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