What is the Angular Speed After Collision?

[sparkle123]

Hello,

I'm having difficulty with this problem.
I'm assuming all the kinetic energy of mass m is transferred to rotational kinetic energy after the collision so
1/2 mv² = 1/2 I ω²
where I is now Md²/12 + m(d/2)² =3/4 md²
Solving, ω = 2v/√3d
But the answer should be 2v/3d.

Thanks!

 

[BruceW]

I agree with your answer for moment of inertia, but I think maybe energy is not conserved in the collision. Think of a quantity which is still conserved, even though energy isn't.

 

[sparkle123]

Got it thanks! :)

 

[Spinnor]

See page 16 (50) of,

http://iweb.tntech.edu/murdock/books/v2chap2.pdf

the problem is close to yours.

Found via,

https://www.google.com/webhp?hl=en#...w.,cf.osb&fp=cb785b2a153d08fa&biw=734&bih=439

 

[sparkle123]

Thanks Spinnor! (: