Two rods each having length l and mass m joined together at point B as shown in figure.Then findout moment of inertia about axis passing thorugh A and perpendicular to the plane of page as shown in figure.

Explanation

We find the resultant moment of inertia I by dividing in two parts such as
I = M.I or rod AB about A +
M.I of rod BC about A
`I = I_1 + I_2" …(1)"`

`I_2 = I_("CM") + md^2`
`=(ml^2)/12 + (5l^2)/4 m " ...(3)"`

Put value from eq (2) & (3) into (1)
`rArr I = (ml^2)/3 + (ml^2)/12 + (ml^2m)/4`
`I = (ml^2)/12 ( 4+ 1+ 15 ) rArr " "I = (5ml^2)/3`