What is the moment of inertia of a pendulum with a mass of #3 kg# that is #1 m# from the pivot?

1 Answer
Jan 15, 2018

Answer:

#3 Kg.m^2#

Explanation:

Here,you will have to consider that the bob of the pendulum is a point mass,because its radius is not given.

so,the given situation comes out to be that a mass of #3Kg# is placed# 1 m# away from a point,so its moment of inertia w.r.t that point will be #mr^2# or #3 Kg.m^2#

if,the radius of the bob was given as# r#,its moment of inertia w.r.t a diameter would be #2/5mr^2# (bob is actually a sphere)

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so,distance between the centre of the bob and the pivoted point would become #(1+r)#

hence,w.r.t the pivoted point moment of inertia would have been# ( 2/5mr^2 + m(1+r)^2)#