Question

If the moment of inertia of a disc about any diameter is 2.5 kgm^2 then its MI about an axis
passing through its centre and perpendicular to its plane is​

Answer 1

Moment of inertia I, for a disc perpendicular to its plane and passing through the centre, I₁ = MR²/2

Moment of inertia I, for a disc perpendicular to its plane and passing through the diameter, I₂ = MR²/4

Since, MR²/4 = 2.5

I₁ = 2I₂

I₁ = 5 kg m²

Answer 2

answer

It is just use of perpendicular axis theorem

Explanation:

If Id be the MI of disc about its diameter Id=2.5kgm²

Then from perpendicular axis theorem Iz=Ix+Iy

we know that MI of disc about diameter Ix=Iy=2.5kgm²

Then Iz=2.5+2.5

Iz=5.0kgm²