Four spheres each diameter 2a and mass 'm' are placed with their centres on the four corners of a square of the side b. Calculate the moment of inertia of the system about any side of the square.

Explanation

`I_(1)=mb^(2)`
`I_(2)=(2)/(5)ma^(2)`
`I_(3)=(2)/(5)ma^(2)`
`I_(4)=mb^(2)`
`therefore` Moment of inertia of the system

`I=I_(1)+I_(2)+I_(3)+I_(4)`
`=mb^(2)+(2)/(5)ma^(2)+(2)/(5)ma^(2)+mb^(2)`
`I=(4)/(5)ma^(2)+2mb^(2)`.