Question

What is the moment of inertia of a pendulum with a mass of `5 kg` that is `9 m` from the pivot?

Answer 1

`I=r^2*m=9^2*5 kg*m^2 = 405 kg*m^2`

Explanation:

The moment of inertia is defined as the distances of all infinitely small masses distributed across the body's whole mass. As an integral:

`I=intr^2dm`

This is useful for bodies of which geometry can be expressed as a function. However, since you only have one body in a very specific spot, it is simply:

`I=r^2*m=9^2*5 kg*m^2 = 405 kg*m^2`