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Moment of Inertia of a Sphere

 

Moment of Inertia of a Sphere Formula, Solid Sphere

I=25mr2 
Symbol English Metric
I = Moment of Inertia lbm/ft2sec kg/m2
m = Mass lbm kg
r = Radius in mm

moment of inertia Sphere solid 1This calculation is for the moment of inertia of a sphere.  There are three separate calculations:  a solid sphere, a hollow sphere and a hollow core sphere.  The difference between a hollow sphere and a hollow core sphere is a hollow sphere has a thin shell, or a thickness that is neglible.  Because a sphere is the same dimensions in every dimension, the moment of inertia is the same about every axis.

Moment of Inertia of a Sphere Formula, Hollow Sphere

I=23mr2 
Symbol English Metric
I = Moment of Inertia lbm/ft2sec kg/m2
m = Mass lbm kg
r = Radius in mm

moment of inertia Sphere solid 1  Piping Designer Logo 1 

 

 

 

 

 

 

Moment of Inertia of a Sphere Formula, Hollow Core Sphere

I=25mr2r52r51r32r31 
Symbol English Metric
I = Moment of Inertia lbm/ft2sec kg/m2
m = Mass lbm kg
r = Radius in mm
r1 = Radius in mm
r2 = Radius in mm

moment of inertia Sphere hollow 1