Rotational Equilibrium and Dynamics -

AI Thread Summary
The discussion centers on calculating the initial and final rotational kinetic energy of a skater who changes his moment of inertia while spinning. The formula for rotational kinetic energy, KE = 1/2·I·ω², is confirmed as correct. The initial moment of inertia is given as 41 kg·m², and the final moment of inertia is 36 kg·m², with the angular speed remaining at 12.0 rad/s. Participants emphasize using the conservation of angular momentum to find the kinetic energy values. The conversation concludes with clarification on using the provided inertia values for calculations.
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Rotational Equilibrium and Dynamics - :)

I'm totally stumped!
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A skater spins with an angular speed of 12.0 rad/s with his arms outstretched. He lowers his arms, decreasing his moment of inertia from 41 kg·m² to 36 kg·m²

Calculate his initial and final rotational kinetic energy.
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Is the formula KE=1/2·I·ω² ?
ω=angular speed.. so ω=12.0 rad/s
so then how would i get I (inertia) ?
and how would i find out initial and final ?
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i just need some help
 
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s the formula KE=1/2·I·ω² ?
yes
so then how would i get I (inertia) ?
its given. read the question

and how would i find out initial and final ?
Use conservation of Angular momentum.
 
^^^
hmm, i think i get it

so.. i use (plug in) 41 kg·m² to get my initial and 36 kg·m² to my my final?
 

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