Question

The axis X and Z in the plane mutually perpendicular and perpendicular to the plane of the disc. if the moment of inertia of the body at axes is respectively $30kg{m}^2$ and $40kg{m}^2$ then M.I about Z axis in $kg{m}^2$ will be:

• A. 70
• B. 50
• C. 10
• D. zero

Answer 1

The correct option is C 10

According to the perpendicular axis theorem:

$I_{axisparalleltotheplane}=\sum I_{axisperpendicularandlyingintheplane}$

Or,

$I_y=I_x+I_z$

Given,

$I_x=30$

$I_z=40$

$\therefore I_z=I_y-I_x$

$I_z=10units$