Question

In the figure given below, the moment of inertia about diametral axis is _______

(a) m(l^2/12 + r^2/4)

(b) m(l^2/6 + r^2/4)

(c) m(l^2/12 + r^2/2)

(d) m(l^2/12 + r^2)

I had been asked this question in class test.

I need to ask this question from Effect of Gyroscopic Couple on a Disc Fixed Rigidly at a Certain Angle to a Rotating Shaft in section Gyroscopic Couple and Precessional Motion of Machine Dynamics

Answer 1

The correct option is (a) m(l^2/12 + r^2/4)

For explanation: If m is the mass, l is the length and r is the radius of the disc, then the moment of inertia about the diametral axis is given by m(l^2/12 + r^2/4).