Particles each of mass 1kg are placed at 1m, 2m and 4m on X-axis with respect to origin. Then moment of inertia of the system about Y-axis is

Options

A. `7kg m^(2)`
B. `14 kg m^(2)`
C. `21 kg m^(2)`
D. `28 kg m^(2)`

Answer

C

Explanation

`I = I_(1)+I_(2)+I_(3)`
`= Mx_(1)^(2)+Mx_(2)^(2)+Mx_(3)^(2)`
`=1xx1+1xx4+1xx16`
`= 1+4+16`
`= 21 kgm^(2)`.