Calculating Final Angular Speed of Rotating Table

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SUMMARY

The discussion focuses on calculating the final angular speed of a rotating table when a 40kg duck moves from a radius of 2.5m to 1.5m. The initial angular speed of the table is 2.0 rad/sec, and the rotational inertia of the table is 250 kg*m². To solve the problem, participants emphasize using the conservation of angular momentum, which states that the initial angular momentum (Iiωi) must equal the final angular momentum (Ifωf). The inertia of the duck must also be included in the calculations to determine the final angular speed.

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  • Understanding of angular momentum conservation
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  • Familiarity with point mass inertia (I = mr²)
  • Basic proficiency in physics equations related to rotational motion
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Homework Statement


a 40kg duck walks from the outside to the inside of a rotating circular table of mass 100kg. if the rotational intertia of the table is 250kg*m^2 and the duck moves from a radius of 2.5m to 1.5m, find the final angular speed of the table if it rotates at 2.0rad/sec at the moment the duck begins to move.

THANKS! I'm studying for a test and i can't do this question



Homework Equations





The Attempt at a Solution



what i did:

L = 250kg * m^2
Wf = ?
Wi = 2 rad /sec
r = 1.5 m

i don't know what to do from here
 
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You'll need to apply conservation of angular momentum given by Iω.

You should also know that for a point mass, like the duck, its inertia at some distance r is mr2. So you need to get I for the table+duck system.

Then just apply the conservation law.
 

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