Question

Calculate the moment of inertia of the thin spherical shell having a mass of 703 kg and diameter of 376 cm.

(a) 1639.89 kgm^2

(b) 1628.47 kgm^2

(c) 1678.12 kgm^2

(d) 1978.19 kgm^2

I have been asked this question in exam.

Question is taken from Methods of Starting Electric Motors in section Starting of Electric Drives

Answer 1

Correct answer is (a) 1639.89 kgm^2

The explanation is: 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=(703)×.66×(1.88)^2=1639.89 kgm^2. It depends upon the orientation of the rotational axis.