Conservation of Angular Momentum

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SUMMARY

The discussion centers on the conservation of angular momentum in a system involving two disks with moments of inertia I and 31, rotating at angular speeds w and 2w, respectively. When the disks are brought together, the final kinetic energy (KE) is calculated to be 49/52 of the initial KE. Key equations include the conservation of angular momentum (Iw = Iw) and the conservation of rotational energy. Understanding these principles is crucial for solving problems related to rotational dynamics.

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  • Understanding of angular momentum and its conservation
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  • Knowledge of rotational kinetic energy calculations
  • Basic algebra for manipulating equations
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Homework Statement


Two disks with moments of inertia I and 31 are mounted on a common shaft with frictionless bearings. They are initially rotating with angular speeds of w and 2w. They are brought together without being disturbed. What is their final KE as a fraction of their initial KE?

The answer is 49/52 but i don't understand the concept of it.
can someone please explain?

Equations:
Angular Momentum: Iw = Iw
 
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You will need to use conservation of angular momentum and conservation of rotational energy.

Start by writing out these quantities for each disk and then when the disks are brought together.
 

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