Arun
Last Activity: 4 Years ago
Mass of the cylinder = m
Outside radius = r₂
Inside radius = r₁
So the axis parallel to its symmetrical axis ( through its centre) and tangential to the outer surface means an axis on the outer surface through the length of the cylinder.
Moment of inertia on the symmetrical axis I₁ = (m/2) (r₁² + r₂²)
Following the parallel axis theorem, moment of inertia on the mentioned axis, I₂ = I₁ + mr₂² [ mass x distance from symmetrical axis ]
that is, I₂ = (m/2) (r₁² + r₂²) + mr₂²
or, I₂ = m [ (r₁²/2) + {(r₂²/2) + r₂²}
or I₂ = (m/2) [ r₁² + 3r₂² ]
So the answer is (m/2) (r₁² + r₂²)
