How Do You Calculate the Angular Momentum of a Rotating Bat?

[Exustior]

Homework Statement

A batter swings a 0.9 m long bat. Calculate the angular momentum of the bat relative to its axis of rotation. Assume the bat has a mass of 0.6 kg and rotates at 3 rad / s
(Hint: Approximate the bat by a rod, or a long thin cylinder, and find the moment of inertia.)
Answer in (N m)

Homework Equations

I=mr^2
ω=v/r
v=ωr
L=Iω

The Attempt at a Solution

L=Iω
I=mr^2
so L=(0.6)(.9^2)(ω)
ω=angular velocity is 3 rad/s
so L=(.6)(.9^2)(3rad/s)= Wrong answer

 

[BruceW]

Hey, welcome to physicsforums!
uh, the moment of inertia formula you have used is not correct for this problem. The inertia I=(0.6)(0.9)^2 would suggest the mass of the bat is concentrated at the end of the bat. But it looks like they want you to assume the bat is a long thin cylinder, of uniform density. So either you can look up the moment of inertia for this kind of object, or derive it yourself, if you have time.

 

[Exustior]

Hey, welcome to physicsforums!
uh, the moment of inertia formula you have used is not correct for this problem. The inertia I=(0.6)(0.9)^2 would suggest the mass of the bat is concentrated at the end of the bat. But it looks like they want you to assume the bat is a long thin cylinder, of uniform density. So either you can look up the moment of inertia for this kind of object, or derive it yourself, if you have time.

Thanks!
I got it I was using the wrong formula.