Three thin uniform rods each of mass M and length L and placed along the three axis of a Cartesian coordinate system with one end of each rod at the origin. The M.I. of the system about z-axis is

Options

A. `(ML^(2))/3`
B. `(2ML^(2))/3`
C. `(2ML^(2))/6`
D. `ML^(2)`

Answer

B

Explanation

`I=Ix+Iy+Iz=(ML^(2))/3+(ML^(2))/3`
`+0=(2ML^(2))/3`
As moment of inertia of rod about its own axis is zero.