(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Derive the moment of inertia for a solid sphere with a uniform mass

2. Relevant equations

[Tex]I= \sum mr^{2}[/tex]

3. The attempt at a solution

I decided to change everything to polar coordinates. Since the polar coordinate substitution is

[tex]\int\int\int_{v} Fr^{2}sin(\phi)drd\phi d\theta[/tex]

I figured that all you should do is plug in the moment of inertia equation into the integral giving you:

[tex]m\int^{2\pi}_{0}\int^{\pi}_{0}\int^{R}_{0} r^{4}sin(\phi)drd\phid\theta =\frac{4\pi R^{5}}{5}[/tex]

however this does not seem to be the correct answer. Can anyone tell me what I'm doing wrong? Thanks in advance for your time and any help.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Deriving the moment of inertia for a sphere

**Physics Forums | Science Articles, Homework Help, Discussion**