Question

Find the moment of inertia of the two uniform joint rods about point `P` as shown in Fig. Use parallel axis theorem. Mass of each rod is `M`.

Answer 1

`I_(P)=I_(P_(1))+I_(P_(2))`

`I_(P)=(Ml^(2))/3+((Ml^(2))/12+Mx^(2))`
`x^(2)=l^(2)+(l/2)^(2)=(5l^(2))/4`
`implies l_(P)=(Ml^(2))/3+[(Ml^(2))/12+M((5l^(2))/4)]=5/3Ml^(2)`