Question

Calculate the moment of inertia of the thin spherical shell having a mass of 7.8 kg and diameter of 145.6 cm.

(a) 2.72 kgm^2

(b) 5.96 kgm^2

(c) 5.45 kgm^2

(d) 2.78 kgm^2

I had been asked this question during a job interview.

I would like to ask this question from Induction Motors in portion Speed Control of Direct Current Motors & Induction Motors of Electric Drives

Answer 1

Right answer is (a) 2.72 kgm^2

To explain: The moment of inertia of the thin spherical shell can be calculated using the formula I=mr^2×.66. The mass of the thin spherical shell and diameter is given. I=(7.8)×.66×(.728)^2=2.72 kgm^2. It depends upon the orientation of the rotational axis.