# What is the moment of inertia of a ball of a mass of 5 Kg and radius of 3 cm?

Nov 4, 2014

The moment of inertia for a solid ball can be calculated using the formula:
$I = \frac{2}{5} m {r}^{2}$
Where m is the mass of the ball and r is the radius.

Wikipedia has a nice list of moments of inertia for various objects. You might notice that the moment of inertia is very different for a sphere which is a thin shell and has all of the mass on the outer surface. An inflatable ball's moment of inertia can be calculated like a thin shell.

http://en.wikipedia.org/wiki/List_of_moments_of_inertia