I need help beginning and solving these 2 connected problems. 2. Dr. Nelson is h

Question

I need help beginning and solving these 2 connected problems.

2. Dr. Nelson is holding two weights at arm's length and spinning on a frictionless turnable at and angular velocity 2.3 rad/s. Dr. Nelson moves the weights inward close to his body and is now spinning at 4.2 rad/s. Find the ratio of the total moment of inertia of Dr. Nelson and the weights at arm's length to the total moment of inertia of Dr. Nelson and the weights pulled inward a. Ror the sn t n configurations. Explain in words why the rotational kinetic energy changed

Explanation / Answer

2] Here angular momentum will be conserved.

i1w1 = i2w2 where i1 and i2 respresnt initial and final moment of inertia, w1 and w2 represent initial and final angular velocity.

RATIO = i1/i2 = w2/w1 = 4.2/2.3 = 1.826 ANSWER

3] Ratio = KE1/KE2 = [0.5i1w1^2]/[0.5i2w2^2]

= w1/w2 because i1w1=i2w2

ratio = 2.3/4.2 = 0.5476

Kinetic energy increased because work has been done by Dr. Nelson in pulling the arms inward.

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