Asked by Anonymous
A man stands on a freely rotating platform, as shown, holding an exercise dumbbell in each hand. With outstretched arms, his angular speed is 1.5 rad/s. After he has pulled his arms in, as shown, his angular speed is 5 rad/s. What is the ratio of his final rotational KE to his initial rotational KE? Explain any differences.
Help please. Use the correct equation then substitute the numbers into that equation
Help please. Use the correct equation then substitute the numbers into that equation
Answers
Answered by
bobpursley
moving ars in decreases the moment of inertia, which if momentum is conserved, angular speed increases
momentums:
initialI*1.5=final*5
finalI/initialI=1.5/5
energy:
finalKE/initialKE= .5finalI*5^2/.5InitialI*1.5^2
or = 1.5/5 * (5^2/1.5^2)=5/1.5
momentums:
initialI*1.5=final*5
finalI/initialI=1.5/5
energy:
finalKE/initialKE= .5finalI*5^2/.5InitialI*1.5^2
or = 1.5/5 * (5^2/1.5^2)=5/1.5
Answered by
Anonymous
What is the answer? Is it 1.998?
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