Question

What is the moment of inertia of an object about an axis if there are three point masses (m₁ = 1.5 kg, m₂ = 1.75 kg, m₃ = 2 kg) located at r₁ = 0.10 m, r₂ = 0.20 m, and r₃ = 0.35 m distance from the axis of rotation?

Options:

A) 2.24 kgm²

B) 29.46 kgm²

^C) 1.20 kgm²

^D) 0.33 kgm²

Answer 1

moment of Inertia is given by = I = m * r²

where m = mass of the object

and r = distance of object from the axis of rotation

in this question

I = m₁ * r₁² + m₂ * r₂² + m₃ * r₃²  

I = ( 1.5 * 0.1² ) + ( 1.75 * 0.2² ) + ( 2 * 0.35² )

I = 0.33 kg - m²

answer option D