Question

Calculate the moment of inertia of an object having time period = 14 sec, mass moment of inertia= 100 Kg-m^2 and the centre of gravity lies at a point 20 cm below the point of suspension.

(a) 9.1

(b) 9.2

(c) 9.3

(d) 10.2

This question was addressed to me in an interview.

The question is from Compound Pendulum topic in division Simple Harmonic Motion of Machine Kinematics

Answer 1

Correct answer is (d) 10.2

For explanation I would say: From the given data it is clear that the given rigid body constitutes a compound pendulum, now the time period of a compound pendulum is given by:

(2π)\(\sqrt{(\frac{I}{mgl})}\)

substituting the values we get

m = 10.2 Kg.