1.

The moment of inertia of a rod about an axis passing through its centre and perpendicular to it is (1)/(12) ML^(2)(where, M is the mass and L the length of the rod.) The rod is bent in the middle so that the two halves make an angle of 30^(@). The moment of inertia of the bent rod about the same axis would be

Answer»

`(1)/(48) ML^(2)`
`(1)/(12) ML^2`
`(1)/(24) ML^2`
`(ML^2)/(8sqrt3)`

Solution :Since, rod is bent at the middle , so each part of it will have same length `((L)/(2))` and mass `((M)/(2))` as shown.

Moment of inertia of each part through its one end = `(1)/(3) ((M)/(2)) ((L)/(2))^(2)`
Hencenet moment of inertia through its middle point O is
`I = (1)/(3) ((M)/(2)) ((L)/(2))^(2) + (1)/(3) ((M)/(2)) ((L)/(2))^(2) = (1)/(3) [ (ML^(2))/(8) + (ML^(2))/(8)] = (ML^(2))/(12)`


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