Rotational Inertia in two cylinders

AI Thread Summary
The discussion focuses on calculating the kinetic energies of two uniform solid cylinders with the same mass and angular velocity but different radii. The first participant used the formula I=mr^2 for rotational inertia and attempted to calculate kinetic energy using 0.5*Iω^2. They encountered issues with unit conversions and ended up with incorrect large values for kinetic energy. The participant mentioned a potential misunderstanding regarding the use of radians and planned to seek clarification from their teacher. The conversation highlights the importance of proper unit handling in rotational dynamics calculations.
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Calculate the kinetic energies of two uniform solid cylinders, each rotating about its central axis. They have the same mass, 1.25 kg, and rotate with the same angular velocity, 235 rad/s, but the first has a radius of 0.18 m and the second a radius of 0.73 m.

I got 12112188.868 for ω, and 0.050625 for I


I have been using I=mr^2, and .5*Iω^2



I plugged everything in without changing any units, and got 1906125390.62499825 for the small one, which i know to be wrong. Then I thought I remembered something my teacher said about multiplying the radians by 2pi, and then I plugged all the numbers back in and got another large number.
 
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nvm, ran out of time. getting help from my teacher tomorrow
 

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