Manipal MET2014PhysicsRotational Motion
Four thin rods of same mass M and same length l , form a square as shown in figure Moment of inertia of this system about an axis through centre O and perpendicular to its plane is
Options
- A4 3 M l^2
- BM l^2 3
- CM l^2 6
- DM l^2 6
Correct answer
A. 4 3 M l^2
Step-by-step solution
Moment of inertia of rod A B about point P= 1 12 M I^2 Ml of rod A B about point O= M l^2 12 +M ( I 2 )^2= 1 3 M l^2 [from the theorem of parallel axis] and the system consists of 4 rods of similar type so by the symmetry I_ system = 4 3 M l^2