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guv

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- Homework Statement
- Imagine a frictionless horizontal table. On the table a uniform cylinder is spinning with one flat face touching the table at angular velocity ##\omega_0##. Through the flat faces of the cylinder, a tiny hole is drilled through. As the cylinder is spinning in place, a pin is inserted through the cylinder very quickly and the cylinder starts to spin around the pin. The horizontal position of the pin does not change (imagine the insertion happens very quickly). Can we apply conservation of energy to find the final angular velocity?

- Relevant Equations
- N/A

We all know we need to apply conservation of angular momentum here. This necessarily leads to a difference in mechanical energy. Since initial rotational inertial is less than final rotational inertia, there is a loss of mechanical energy. However, I have not been able to convince myself what's doing work to take away the mechanical energy of the disk? Or is it because the problem is set up in a too idealistic way? Thanks,