# What is radius of gyration?

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please tell me in simple words.......i find hard to understand

please tell me in simple words.......i find hard to understand

##### 1 Answer

Jan 6, 2018

see below

#### Explanation:

consider the two diagrams above

In diagram 1 we have a shape rotating about an axis. If the mass is

then its moment of inertia is

in diagram 2 we have the same axis of rotation but this time the same mass is concentrated at a point.

its moment of inertia is

if the two values of the moments of inertia are the same

then

in other words the radius of gyration is the distance from the axis of rotation at which the total mass of a body is assumed concentrated and at which the moment of inertia will be equal to the actual moment of inertia of the body.

so