# What is the moment of inertia of a pendulum with a mass of 7 kg that is 4 m from the pivot?

Jan 13, 2016

$112 k g . {m}^{2}$

#### Explanation:

Assuming this is a simple pendulum, ie the mass and dimensions of the pendulum bob is small compared to its overall dimensions, we may simple approximate its moment of inertia as follows :

$I = M {R}^{2}$

$= 7 \times {4}^{2}$

$= 112 k g . {m}^{2}$.

(If however the pendulum is compound, then one would need to use alternative formulae involving centre of mass and precise definitions of $I$).