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Is the answer not 453.6926 J or 5*10^2 J, I copied the exact calculations from your final answer of part A (3:49) and did not get 5*10^16 J.
And I also you changed the angular velocity from 3.333*10^-4 to 3.333*10^-11 when doing the calculations to work out the KE
Hello student from thesoutportschool, thank you for spotting the error. At 3:23 I mention correctly that the angular velocity is , whereas at 3:46 I incorrectly wrote . My calculations were nevertheless done using , so the results are correct. I'll put a note above the video to use for the angular velocity.
All the best,