Question

Calculate the moment of inertia of the hollow cylinder having a mass of 78 kg and radius of 49 cm.

(a) 9.363 kgm^2

(b) 9.265 kgm^2

(c) 9.787 kgm^2

(d) 9.568 kgm^2

The question was posed to me in unit test.

This interesting question is from Modified Speed Torque Characteristics of DC Series Motors in section Characteristics of DC & AC Motors of Electric Drives

Answer 1

The correct option is (a) 9.363 kgm^2

The best I can explain: The moment of inertia of the hollow cylinder can be calculated using the formula I=miri^2÷2. The mass of the hollow cylinder and radius is given. I=(78)×.5×(.49)^2=9.363 kgm^2. It depends upon the orientation of the rotational axis.