What is the Angular Speed After Collision?

AI Thread Summary
The discussion centers on calculating the angular speed after a collision involving a mass and a rod. The initial assumption is that all kinetic energy is converted to rotational kinetic energy, leading to the equation ω = 2v/√3d. However, there is a suggestion that energy may not be conserved during the collision, prompting a reevaluation of the conservation principles at play. A reference is provided for further reading on similar problems. The conversation highlights the complexity of energy conservation in collision scenarios.
sparkle123
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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!
 

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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.
 
Got it thanks! :)
 
Last edited:
Thanks Spinnor! (:
 

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