# Angular Momentum of a Baseball/MasteringPhysics Tech Support

## Homework Statement

A 7.3-cm-diameter baseball has mass of 150 g and is spinning at 230 rad/s .
Treating the baseball as a uniform solid sphere, what is its angular momentum?

I'm about to pull my hair out because I feel like I understand everything about this problem perfectly and yet I'm still getting back sass from MasteringPhysics.
But, hey I'm not the smartest guy out there so I've probably actually got it wrong.

## Homework Equations

Moment of inertia of a uniform solid sphere:
2/5*MR^2

L=Iω

## The Attempt at a Solution

.4*.15*.073^2=.00031974J=I
Iω=.00031974*230=.0735402J*s=L

This is apparently wrong; yes I've attempted giving them the 2 significant figures they asked for.

Including unit conversion, this seems like nothing more than physics flavored 9th grade algebra, which is exactly why I'm worried enough about it to come seek help.

TSny
Homework Helper
Gold Member
Did you use the diameter where you meant to use the radius?

Thanks for replying! I'm an idiot.

TSny
Homework Helper
Gold Member
I'm an idiot.
No, just an oversight. Easy to do.