Question

What is radius of gyration?

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

Answer 1

see below

Explanation:

consider the two diagrams above

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

then its moment of inertia is

`I=mr^2`

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

`I'=Mk^2`

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

then `k` is called the radius of gyration#

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

`I=Mk^2`

`:.k=sqrt(I/M)`